Articles | Volume 12, issue 5 
            
                
                    
            
            
            https://doi.org/10.5194/cp-12-1215-2016
                    © Author(s) 2016. This work is distributed under 
the Creative Commons Attribution 3.0 License.
                the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/cp-12-1215-2016
                    © Author(s) 2016. This work is distributed under 
the Creative Commons Attribution 3.0 License.
                the Creative Commons Attribution 3.0 License.
Technical note: Estimating unbiased transfer-function performances in spatially structured environments
Mathias Trachsel
CORRESPONDING AUTHOR
                                            
                                    
                                            Department of Biology, University of Bergen, PO Box 7803,
5020 Bergen, Norway
                                        
                                    
                                            currently at: Department of Geology, University of Maryland, College Park,
MD 20742, USA
                                        
                                    Richard J. Telford
                                            Department of Biology, University of Bergen, PO Box 7803,
5020 Bergen, Norway
                                        
                                    
                                            Bjerknes Centre for Climate Research, Bergen,
Norway
                                        
                                    Related authors
Kira Rehfeld, Mathias Trachsel, Richard J. Telford, and Thomas Laepple
                                    Clim. Past, 12, 2255–2270, https://doi.org/10.5194/cp-12-2255-2016, https://doi.org/10.5194/cp-12-2255-2016, 2016
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                                                Indirect evidence on past climate comes from the former composition of ecological communities such as plants, preserved as pollen grains in sediments of lakes. Transfer functions convert relative counts of species to a climatologically meaningful scale (e.g. annual mean temperature in degrees C). We show that the fundamental assumptions in the algorithms impact the reconstruction results in he idealized model world, in particular if the reconstructed variables were not ecologically relevant.
                                            
                                            
                                        M. Trachsel and A. Nesje
                                    The Cryosphere, 9, 1401–1414, https://doi.org/10.5194/tc-9-1401-2015, https://doi.org/10.5194/tc-9-1401-2015, 2015
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                                                We employ statistical models to model annual glacier mass balances of eight Scandinavian glaciers as function of summer temperature and winter precipitation.
Relative importances of winter precipitation and summer temperature vary in time.
Relative importances are influenced by AMO and NAO.
                                            
                                            
                                        Nadia Al-Sabouni, Isabel S. Fenton, Richard J. Telford, and Michal Kučera
                                    J. Micropalaeontol., 37, 519–534, https://doi.org/10.5194/jm-37-519-2018, https://doi.org/10.5194/jm-37-519-2018, 2018
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                                                In this study we investigate consistency in species-level identifications and whether disagreements are predictable. Overall, 21 researchers from across the globe identified sets of 300 specimens or digital images of planktonic foraminifera. Digital identifications tended to be more disparate. Participants trained by the same person often had more similar identifications. Disagreements hardly affected transfer-function temperature estimates but produced larger differences in diversity metrics.
                                            
                                            
                                        Kira Rehfeld, Mathias Trachsel, Richard J. Telford, and Thomas Laepple
                                    Clim. Past, 12, 2255–2270, https://doi.org/10.5194/cp-12-2255-2016, https://doi.org/10.5194/cp-12-2255-2016, 2016
                                    Short summary
                                    Short summary
                                            
                                                Indirect evidence on past climate comes from the former composition of ecological communities such as plants, preserved as pollen grains in sediments of lakes. Transfer functions convert relative counts of species to a climatologically meaningful scale (e.g. annual mean temperature in degrees C). We show that the fundamental assumptions in the algorithms impact the reconstruction results in he idealized model world, in particular if the reconstructed variables were not ecologically relevant.
                                            
                                            
                                        M. Trachsel and A. Nesje
                                    The Cryosphere, 9, 1401–1414, https://doi.org/10.5194/tc-9-1401-2015, https://doi.org/10.5194/tc-9-1401-2015, 2015
                                    Short summary
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                                                We employ statistical models to model annual glacier mass balances of eight Scandinavian glaciers as function of summer temperature and winter precipitation.
Relative importances of winter precipitation and summer temperature vary in time.
Relative importances are influenced by AMO and NAO.
                                            
                                            
                                        R. J. Telford, C. Li, and M. Kucera
                                    Clim. Past, 9, 859–870, https://doi.org/10.5194/cp-9-859-2013, https://doi.org/10.5194/cp-9-859-2013, 2013
                            Related subject area
            Subject: Proxy Use-Development-Validation | Archive: Marine Archives | Timescale: Holocene
            
                    
                        
                            
                            
                                     
                                Glacial–interglacial seawater isotope change near the Chilean Margin as reflected by δ2H values of C37 alkenones
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Upper-ocean temperature characteristics in the subantarctic southeastern Pacific based on biomarker reconstructions
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Evaluation of the distributions of hydroxylated glycerol dibiphytanyl glycerol tetraethers (GDGTs) in Holocene Baltic Sea sediments for reconstruction of sea surface temperature: the effect of changing salinity
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Technical Note: Past and future warming – direct comparison on multi-century timescales
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Co-evolution of the terrestrial and aquatic ecosystem in the Holocene Baltic Sea
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Holocene palaeoceanography of the Northeast Greenland shelf
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A spectral approach to estimating the timescale-dependent uncertainty of paleoclimate records – Part 2: Application and interpretation
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Evaluation of oxygen isotopes and trace elements in planktonic foraminifera from the Mediterranean Sea as recorders of seawater oxygen isotopes and salinity
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                A spectral approach to estimating the timescale-dependent uncertainty of paleoclimate records – Part 1: Theoretical concept
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Can morphological features of coccolithophores serve as a reliable proxy to reconstruct environmental conditions of the past?
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Evidence from giant-clam δ18O of intense El Ninõ–Southern Oscillation-related variability but reduced frequency 3700 years ago
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Empirical estimate of the signal content of Holocene temperature proxy records
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Sedproxy: a forward model for sediment-archived climate proxies
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                                     
                                Tracing winter temperatures over the last two millennia using a north-east Atlantic coastal record
                                
                                        
                                            
                                    
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                The 3.6 ka Aniakchak tephra in the Arctic Ocean: a constraint on the Holocene radiocarbon reservoir age in the Chukchi Sea
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Sedimentary archives of climate and sea-level changes during the Holocene in the Rhône prodelta (NW Mediterranean Sea)
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Holocene hydrological changes in the Rhône River (NW Mediterranean) as recorded in the marine mud belt
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Holocene climate variability in the North-Western Mediterranean Sea (Gulf of Lions)
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Eastern Mediterranean Sea circulation inferred from the conditions of S1 sapropel deposition
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Evidence for the non-influence of salinity variability on the Porites coral Sr/Ca palaeothermometer
                                
                                        
                                            
                                    
                            
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Holocene sub-centennial evolution of Atlantic water inflow and sea ice distribution in the western Barents Sea
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Long-term variations in Iceland–Scotland overflow strength during the Holocene
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Seemingly divergent sea surface temperature proxy records in the central Mediterranean during the last deglaciation
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Natural variability and anthropogenic effects in a Central Mediterranean core
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                The extra-tropical Northern Hemisphere temperature in the last two millennia: reconstructions of low-frequency variability
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Tracking climate variability in the western Mediterranean during the Late Holocene: a multiproxy approach
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Late Holocene climate variability in the southwestern Mediterranean region: an integrated marine and terrestrial geochemical approach
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Holocene trends in the foraminifer record from the Norwegian Sea and the North Atlantic Ocean
                                
                            
                            
                        
                    
                    
                        
                            
                            
                            
                                     
                                Terrestrial climate variability and seasonality changes in the Mediterranean region between 15 000 and 4000 years BP deduced from marine pollen records
                                
                            
                            
                        
                    
                    
            
        
        Katrin Hättig, Devika Varma, Stefan Schouten, and Marcel T. J. van der Meer
                                    Clim. Past, 19, 1919–1930, https://doi.org/10.5194/cp-19-1919-2023, https://doi.org/10.5194/cp-19-1919-2023, 2023
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                                                Water isotopes, both hydrogen and oxygen, correlate with the salinity of the sea. Here we reconstruct the surface seawater isotopic composition during the last deglaciation based on the measured hydrogen isotopic composition of alkenones, organic compounds derived from haptophyte algae, and compared it to oxygen isotopes of calcite shells produced in the bottom water. Our results suggest that surface seawater experienced more freshening during the last 20 000 years than the bottom seawater.
                                            
                                            
                                        Julia Rieke Hagemann, Lester Lembke-Jene, Frank Lamy, Maria-Elena Vorrath, Jérôme Kaiser, Juliane Müller, Helge W. Arz, Jens Hefter, Andrea Jaeschke, Nicoletta Ruggieri, and Ralf Tiedemann
                                    Clim. Past, 19, 1825–1845, https://doi.org/10.5194/cp-19-1825-2023, https://doi.org/10.5194/cp-19-1825-2023, 2023
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                                                Alkenones and glycerol dialkyl glycerol tetraether lipids (GDGTs) are common biomarkers for past water temperatures. In high latitudes, determining temperature reliably is challenging. We analyzed 33 Southern Ocean sediment surface samples and evaluated widely used global calibrations for both biomarkers. For GDGT-based temperatures, previously used calibrations best reflect temperatures >5° C; (sub)polar temperature bias necessitates a new calibration which better aligns with modern values.
                                            
                                            
                                        Jaap S. Sinninghe Damsté, Lisa A. Warden, Carlo Berg, Klaus Jürgens, and Matthias Moros
                                    Clim. Past, 18, 2271–2288, https://doi.org/10.5194/cp-18-2271-2022, https://doi.org/10.5194/cp-18-2271-2022, 2022
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                                                Reconstruction of past climate conditions is important for understanding current climate change. These reconstructions are derived from proxies, enabling reconstructions of, e.g., past temperature, precipitation, vegetation, and sea surface temperature (SST). Here we investigate a recently developed SST proxy based on membrane lipids of ammonium-oxidizing archaea in the ocean. We show that low salinities substantially affect the proxy calibration by examining Holocene Baltic Sea sediments.
                                            
                                            
                                        Darrell S. Kaufman and Nicholas P. McKay
                                    Clim. Past, 18, 911–917, https://doi.org/10.5194/cp-18-911-2022, https://doi.org/10.5194/cp-18-911-2022, 2022
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                                                Global mean surface temperatures are rising to levels unprecedented in over 100 000 years. This conclusion takes into account both recent global warming and likely future warming, which thereby enables a direct comparison with paleotemperature reconstructions on multi-century timescales.
                                            
                                            
                                        Gabriella M. Weiss, Julie Lattaud, Marcel T. J. van der Meer, and Timothy I. Eglinton
                                    Clim. Past, 18, 233–248, https://doi.org/10.5194/cp-18-233-2022, https://doi.org/10.5194/cp-18-233-2022, 2022
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                                                Here we study the elemental signatures of plant wax compounds as well as molecules from algae and bacteria to understand how water sources changed over the last 11 000 years in the northeastern part of Europe surrounding the Baltic Sea. Our results show diversity in plant and aquatic microorganisms following the melting of the large ice sheet that covered northern Europe as the regional climate continued to warm. A shift in water source from ice melt to rain also occurred around the same time.
                                            
                                            
                                        Teodora Pados-Dibattista, Christof Pearce, Henrieka Detlef, Jørgen Bendtsen, and Marit-Solveig Seidenkrantz
                                    Clim. Past, 18, 103–127, https://doi.org/10.5194/cp-18-103-2022, https://doi.org/10.5194/cp-18-103-2022, 2022
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                                                We carried out foraminiferal, stable isotope, and sedimentological analyses of a marine sediment core retrieved from the Northeast Greenland shelf. This region is highly sensitive to climate variability because it is swept by the East Greenland Current, which is the main pathway for sea ice and cold waters that exit the Arctic Ocean. The palaeoceanographic reconstruction reveals significant variations in the water masses and in the strength of the East Greenland Current over the last 9400 years.
                                            
                                            
                                        Andrew M. Dolman, Torben Kunz, Jeroen Groeneveld, and Thomas Laepple
                                    Clim. Past, 17, 825–841, https://doi.org/10.5194/cp-17-825-2021, https://doi.org/10.5194/cp-17-825-2021, 2021
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                                                Uncertainties in climate proxy records are temporally autocorrelated. By deriving expressions for the power spectra of errors in proxy records, we can estimate appropriate uncertainties for any timescale, for example, for temporally smoothed records or for time slices. Here we outline and demonstrate this approach for climate proxies recovered from marine sediment cores.
                                            
                                            
                                        Linda K. Dämmer, Lennart de Nooijer, Erik van Sebille, Jan G. Haak, and Gert-Jan Reichart
                                    Clim. Past, 16, 2401–2414, https://doi.org/10.5194/cp-16-2401-2020, https://doi.org/10.5194/cp-16-2401-2020, 2020
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                                                The compositions of foraminifera shells often vary with environmental parameters such as temperature or salinity; thus, they can be used as proxies for these environmental variables. Often a single proxy is influenced by more than one parameter. Here, we show that while salinity impacts shell Na / Ca, temperature has no effect. We also show that the combination of different proxies (Mg / Ca and δ18O) to reconstruct salinity does not seem to work as previously thought.
                                            
                                            
                                        Torben Kunz, Andrew M. Dolman, and Thomas Laepple
                                    Clim. Past, 16, 1469–1492, https://doi.org/10.5194/cp-16-1469-2020, https://doi.org/10.5194/cp-16-1469-2020, 2020
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                                                This paper introduces a method to estimate the uncertainty of climate reconstructions from single sediment proxy records. The method can compute uncertainties as a function of averaging timescale, thereby accounting for the fact that some components of the uncertainty are autocorrelated in time. This is achieved by treating the problem in the spectral domain. Fully analytic expressions are derived. A companion paper (Part 2) complements this with application-oriented examples of the method.
                                            
                                            
                                        Giulia Faucher, Ulf Riebesell, and Lennart Thomas Bach
                                    Clim. Past, 16, 1007–1025, https://doi.org/10.5194/cp-16-1007-2020, https://doi.org/10.5194/cp-16-1007-2020, 2020
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                                                We designed five experiments choosing different coccolithophore species that have been evolutionarily distinct for millions of years. If all species showed the same morphological response to an environmental driver, this could be indicative of a response pattern that is conserved over geological timescales. We found an increase in the percentage of malformed coccoliths under altered CO2, providing evidence that this response could be used as paleo-proxy for episodes of acute CO2 perturbations.
                                            
                                            
                                        Yue Hu, Xiaoming Sun, Hai Cheng, and Hong Yan
                                    Clim. Past, 16, 597–610, https://doi.org/10.5194/cp-16-597-2020, https://doi.org/10.5194/cp-16-597-2020, 2020
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                                                Tridacna, as the largest marine bivalves, can be used for high-resolution paleoclimate reconstruction in its carbonate skeleton. In this contribution, the modern δ18O shell is suggested to be a proxy for sea surface temperature in the Xisha Islands, South China Sea. Data from a fossil Tridacna (3673 ± 28 BP) indicate a warmer climate and intense ENSO-related variability but reduced ENSO frequency and more extreme El Niño winters compared to modern Tridacna.
                                            
                                            
                                        Maria Reschke, Kira Rehfeld, and Thomas Laepple
                                    Clim. Past, 15, 521–537, https://doi.org/10.5194/cp-15-521-2019, https://doi.org/10.5194/cp-15-521-2019, 2019
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                                                We empirically estimate signal-to-noise ratios of temperature proxy records used in global compilations of the middle to late Holocene by comparing the spatial correlation structure of proxy records and climate model simulations accounting for noise and time uncertainty. We find that low signal contents of the proxy records or, alternatively, more localised climate variations recorded by proxies than suggested by current model simulations suggest caution when interpreting multi-proxy datasets.
                                            
                                            
                                        Andrew M. Dolman and Thomas Laepple
                                    Clim. Past, 14, 1851–1868, https://doi.org/10.5194/cp-14-1851-2018, https://doi.org/10.5194/cp-14-1851-2018, 2018
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                                                Climate proxies from marine sediments provide an important record of past temperatures, but contain noise from many sources. These include mixing by burrowing organisms, seasonal and habitat biases, measurement error, and small sample size effects. We have created a forward model that simulates the creation of proxy records and provides it as a user-friendly R package. It allows multiple sources of uncertainty to be considered together when interpreting proxy climate records.
                                            
                                            
                                        Irina Polovodova Asteman, Helena L. Filipsson, and Kjell Nordberg
                                    Clim. Past, 14, 1097–1118, https://doi.org/10.5194/cp-14-1097-2018, https://doi.org/10.5194/cp-14-1097-2018, 2018
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                                                We present 2500 years of winter temperatures, using a sediment record from Gullmar Fjord analyzed for stable oxygen isotopes in benthic foraminifera. Reconstructed temperatures are within the annual temperature variability recorded in the fjord since the 1890s. Results show the warm Roman and Medieval periods and the cold Little Ice Age. The record also shows the recent warming, which does not stand out in the 2500-year perspective and is comparable to the Roman and Medieval climate anomalies.
                                            
                                            
                                        Christof Pearce, Aron Varhelyi, Stefan Wastegård, Francesco Muschitiello, Natalia Barrientos, Matt O'Regan, Thomas M. Cronin, Laura Gemery, Igor Semiletov, Jan Backman, and Martin Jakobsson
                                    Clim. Past, 13, 303–316, https://doi.org/10.5194/cp-13-303-2017, https://doi.org/10.5194/cp-13-303-2017, 2017
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                                                The eruption of the Alaskan Aniakchak volcano of 3.6 thousand years ago was one of the largest Holocene eruptions worldwide. The resulting ash is found  in several Alaskan sites and as far as Newfoundland and Greenland. In this study, we found ash from the Aniakchak eruption in a marine sediment core from the western Chukchi Sea in the Arctic Ocean. Combined with radiocarbon dates on mollusks, the volcanic age marker is used to calculate the marine radiocarbon reservoir age at that time.
                                            
                                            
                                        Anne-Sophie Fanget, Maria-Angela Bassetti, Christophe Fontanier, Alina Tudryn, and Serge Berné
                                    Clim. Past, 12, 2161–2179, https://doi.org/10.5194/cp-12-2161-2016, https://doi.org/10.5194/cp-12-2161-2016, 2016
                            Maria-Angela Bassetti, Serge Berné, Marie-Alexandrine Sicre, Bernard Dennielou, Yoann Alonso, Roselyne Buscail, Bassem Jalali, Bertil Hebert, and Christophe Menniti
                                    Clim. Past, 12, 1539–1553, https://doi.org/10.5194/cp-12-1539-2016, https://doi.org/10.5194/cp-12-1539-2016, 2016
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                                                This work represents the first attempt to decipher the linkages between rapid climate changes and continental Holocene paleohydrology in the NW Mediterranean shallow marine setting. Between 11 and 4 ka cal BP, terrigenous input increased and reached a maximum at 7 ka cal BP, probably as a result of a humid phase. From ca. 4 ka cal BP to the present, enhanced variability in the land-derived material is possibly due to large-scale atmospheric circulation and rainfall patterns in western Europe.
                                            
                                            
                                        B. Jalali, M.-A. Sicre, M.-A. Bassetti, and N. Kallel
                                    Clim. Past, 12, 91–101, https://doi.org/10.5194/cp-12-91-2016, https://doi.org/10.5194/cp-12-91-2016, 2016
                            K. Tachikawa, L. Vidal, M. Cornuault, M. Garcia, A. Pothin, C. Sonzogni, E. Bard, G. Menot, and M. Revel
                                    Clim. Past, 11, 855–867, https://doi.org/10.5194/cp-11-855-2015, https://doi.org/10.5194/cp-11-855-2015, 2015
                            M. Moreau, T. Corrège, E. P. Dassié, and F. Le Cornec
                                    Clim. Past, 11, 523–532, https://doi.org/10.5194/cp-11-523-2015, https://doi.org/10.5194/cp-11-523-2015, 2015
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                                                The influence of salinity on the Porites Sr/Ca palaeothermometer is still poorly documented. We test the salinity effect on Porites Sr/Ca-based SST reconstructions using a large spatial compilation of published Porites data from the Pacific, Indian Ocean, and the Red Sea. We find no evidence of a salinity bias in the Sr/Ca SST proxy at monthly and interannual timescales using two different salinity products. This result is in agreement with laboratory experiments on coral species.
                                            
                                            
                                        S. M. P. Berben, K. Husum, P. Cabedo-Sanz, and S. T. Belt
                                    Clim. Past, 10, 181–198, https://doi.org/10.5194/cp-10-181-2014, https://doi.org/10.5194/cp-10-181-2014, 2014
                            D. J. R. Thornalley, M. Blaschek, F. J. Davies, S. Praetorius, D. W. Oppo, J. F. McManus, I. R. Hall, H. Kleiven, H. Renssen, and I. N. McCave
                                    Clim. Past, 9, 2073–2084, https://doi.org/10.5194/cp-9-2073-2013, https://doi.org/10.5194/cp-9-2073-2013, 2013
                            M.-A. Sicre, G. Siani, D. Genty, N. Kallel, and L. Essallami
                                    Clim. Past, 9, 1375–1383, https://doi.org/10.5194/cp-9-1375-2013, https://doi.org/10.5194/cp-9-1375-2013, 2013
                            S. Alessio, G. Vivaldo, C. Taricco, and M. Ghil
                                    Clim. Past, 8, 831–839, https://doi.org/10.5194/cp-8-831-2012, https://doi.org/10.5194/cp-8-831-2012, 2012
                            B. Christiansen and F. C. Ljungqvist
                                    Clim. Past, 8, 765–786, https://doi.org/10.5194/cp-8-765-2012, https://doi.org/10.5194/cp-8-765-2012, 2012
                            V. Nieto-Moreno, F. Martínez-Ruiz, S. Giralt, F. Jiménez-Espejo, D. Gallego-Torres, M. Rodrigo-Gámiz, J. García-Orellana, M. Ortega-Huertas, and G. J. de Lange
                                    Clim. Past, 7, 1395–1414, https://doi.org/10.5194/cp-7-1395-2011, https://doi.org/10.5194/cp-7-1395-2011, 2011
                            C. Martín-Puertas, F. Jiménez-Espejo, F. Martínez-Ruiz, V. Nieto-Moreno, M. Rodrigo, M. P. Mata, and B. L. Valero-Garcés
                                    Clim. Past, 6, 807–816, https://doi.org/10.5194/cp-6-807-2010, https://doi.org/10.5194/cp-6-807-2010, 2010
                            C. Andersson, F. S. R. Pausata, E. Jansen, B. Risebrobakken, and R. J. Telford
                                    Clim. Past, 6, 179–193, https://doi.org/10.5194/cp-6-179-2010, https://doi.org/10.5194/cp-6-179-2010, 2010
                            I. Dormoy, O. Peyron, N. Combourieu Nebout, S. Goring, U. Kotthoff, M. Magny, and J. Pross
                                    Clim. Past, 5, 615–632, https://doi.org/10.5194/cp-5-615-2009, https://doi.org/10.5194/cp-5-615-2009, 2009
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                Short summary
            In spatially structured environments, conventional cross validation results in over-optimistic transfer function performance estimates. H-block cross validation, where all samples within h kilometres of the test samples are omitted is a method for obtaining unbiased transfer function performance estimates. We assess three methods for determining the optimal h using simulated data and published transfer functions. Some transfer functions perform notably worse when h-block cross validation is used.
            In spatially structured environments, conventional cross validation results in over-optimistic...
            
         
 
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
                        
                                         
             
             
             
            