Reconstruction of the paleoclimate
Our long-standing collaboration with the paleoeclimate community has centered on using lake sediment fossil records to reconstruct past climate variation. In particular, statistical scale space methods have been developed for the quantification of credible climate features in different time scales in the presence of uncertainties caused by reconstruction and dating errors. Tutorials on the relevant scale space techniques, including the original inspiration, SiZer, and our Bayesian variant, BSiZer, summarize the main ideas. Important on-going work involves also Bayesian spatio-temporal temperature reconstructions using several sediment cores simultaneously.
BSiZer analysis of a diatom fossil based temperature reconstruction in northern Fennoscandia for the last 800 years. The upper panel: the reconstructed temperatures shown as dots together with three smooths obtained as posterior means. The lower panel: BSiZer map with the three smoothing levels shown using the same colors as in the upper panel. Red and blue indicate credibly warming and cooling climate, respectively.
Selected papers:
- A. Korhola, J. Weckström, L. Holmström, and P. Erästö. A quantitative Holocene climatic record from diatoms in northern Fennoscandia. Quaternary Research, 54:284-294, 2000.
- L. Holmström and P. Erästö. Making inferences about past environmental change using smoothing in multiple time scales. Computational Statistics & Data Analysis, 41(2):289-309, 2002.
- P. Erästö and L. Holmström. Bayesian multiscale smoothing for making inferences about features in scatter plots. Journal of Computational and Graphical Statistics, 14(3):569-589, 2005.
- P. Erästö and L. Holmström. Prior selection and multiscale analysis in Bayesian temperature reconstruction based on species assemblages. Journal of Paleolimnology, 36(1):69-80, 2006.
- J. Weckström, A. Korhola, P. Erästö, and L. Holmström. Temperature Patterns over the Past Eight Centuries in Northern Fennoscandia Inferred from Sedimentary Diatoms. Quaternary Research, 66:78-86, 2006.
- P. Erästö and L. Holmström. Bayesian analysis of features in a scatter plot with dependent observations and errors in predictors. Journal of Statistical Computation and Simulation, 77(5):421-431, 2007.
- L. Holmström. BSiZer. Wiley Interdisciplinary Reviews: Computational Statistics, 2(5):526-534, 2010. Available on-line at http://dx.doi.org/10.1002/wics.115 .
- L. Holmström. Scale space methods. Wiley Interdisciplinary Reviews: Computational Statistics, 2(2):150-159, 2010. Available on-line at http://dx.doi.org/10.1002/wics.79 .
- L. Holmström. Discussion of: A statistical analysis of multiple temperature proxies: are reconstructions of surface temperatures over the last 1000 years reliable? by B. B. McShane and A. J. Wyner. The Annals of Applied Statistics, 5(1):71 - 75, 2011. Available on-line at http://dx.doi.org/10.1214/10-AOAS398H .
- P. Erästö, L. Holmström, A. Korhola, and J. Weckström. Finding a consensus on credible features among several paleoclimate reconstructions. Annals of Applied Statistics, 6(4):1377-1405, 2012. Available on-line at http://dx.doi.org/10.1214/12-AOAS540 , and also at http://cc.oulu.fi/~llh/preprints/Consensus.zip .
- F. Godtliebsen, L. Holmström, A. Miettinen, P. Erästö, D. V. Divine, and N. Koc. Pairwise Scale-Space Comparison of Time Series with Application to Climate Research. Journal of Geophysical Research, 117, C03046, 2012. Available on-line at http://dx.doi.org/10.1029/2011JC007546 .
- S. Salonen, L. Ilvonen, H. Seppä, L. Holmström, R. J. Telford, A. Gaidamavicius, M. Stancikaite, and D. Subetto. Comparing different calibration methods (WA/WAPLS regression and Bayesian modelling) and different-sized calibration sets in pollen-based quantitative climate reconstruction. The Holocene, 22(4):413 - 424, 2012.
- L. Holmström, L. Ilvonen, H. Seppä, and S. Veski. A Bayesian spatiotemporal model for reconstructing climate from multiple pollen records. The Annals of Applied Statistics, 9(3):1194-1225, 2015. Available on-line at http://dx.doi.org/10.1214/15-AOAS832, and also at http://cc.oulu.fi/~llh/preprints/Spattemp.zip.
- J. Li, L. Ilvonen, Q. Xu, J. Ni, L. Jin, L. Holmström, X. Cao, Z. Zheng, H. Lu, Y. Luo, Y. Li, C. Li, X. Zhang, and H. Seppä. East Asian summer monsoon precipitation variations in monsoonal China over the last 9500 years: a comparison of pollen-based reconstructions and model simulations. The Holocene, 26(4):592-602, 2016.
- L. Ilvonen, L. Holmström, H. Seppä, and S. Veski. A Bayesian multinomial regression model for paleoclimate reconstruction with time uncertainty. Environmetrics, 27(7):409-422, 2016. Available on-line at http://dx.doi.org/10.1002/env.2393.
- L. Ilvonen, L. Holmström, H. Seppä, and S. Veski. Rejoinder. Environmetrics, 27(7):434-438, 2016. Available on-line at http://dx.doi.org/ 10.1002/env.2409.
- T. Aakala, L. Pasanen, S. Helama, V. Vakkari, I. Drobyshev, T. Kuuluvainen, H. Seppä, N. Stivrins, T. Wallenius, H. Vasander, and L. Holmström. Multiscale variation in drought controlled historical forest fire activity in the European boreal forest. Ecological Monographs, 88(1):74-91, 2018. Available on-line at http://dx.doi.org/10.1002/ecm.1276.
- K. Fang, D. Chen, L. Ilvonen, D. Frank, L. Pasanen, L. Holmström, Y. Zhao, P. Zhang, and H. Seppä. Time-varying relationships among oceanic and atmospheric modes: A turning point at around 1940. Quaternary International, 487:12-25, 2018. Available on-line at https://doi.org/10.1016/j.quaint.2017.09.005.
- N. Kulha, L. Pasanen, L. Holmström, L. De Grandpré, S. Gauthier, T. Kuuluvainen, and T. Aakala. Identifying the spatial scales of forest structural change in two boreal regions. In 5th European Congress of Conservation Biology. University of Jyväskylä, 2018. Available on-line at https://doi.org/110.17011/conference/eccb2018/107590.
- L. Pasanen, T. Aakala, and L. Holmström. A scale space approach for estimating the characteristic feature sizes in hierarchical signals. Stat, 7(1):e195, 2018. Available on-line at https://onlinelibrary.wiley.com/ doi/abs/10.1002/sta4.195.
- K. Fang, D. Chen, L. Ilvonen, L. Pasanen, L. Holmström, H. Seppä, G. Huang, T. Ou, and H. Linderholm. Oceanic and atmospheric modes in the Pacific and Atlantic Oceans since the Little Ice Age (LIA): towards a synthesis. Quaternary Science Reviews, 215:293-307, 2019. Available on-line at http://www.sciencedirect.com/science/article/pii/S0277379118308886.
- N. Kulha, L. Pasanen, L. Holmström, Louis De Grandpré, T. Kuuluvainen, and T. Aakala. At What Scales and Why Does Forest Structure Vary in Naturally Dynamic Boreal Forests? An Analysis of Forest Landscapes on Two Continents. Ecosystems, 22(4):709-724, 2019. Available on-line at https://doi.org/10.1007/s10021-018-0297-2.
- M. Latalowa, J. Swieta-Musznicka, M. Slowinski, A. Pedziszewska, A. Noryskiewicz, M. Zimny, M. Obremska, F. Ott, N. Stivrins, L. Pasanen, L. Ilvonen, L. Holmström, and H. Seppä. Abrupt Alnus population decline at the end of the first millennium CE in Europe - the event ecology, possible causes, and implications. The Holocene, 29(8):1335-1349, 2019. Available on-line at https://doi.org/10.1177/0959683619846978.
- N. Stivrins, T. Aakala, L. Ilvonen, L. Pasanen, T. Kuuluvainen, H. Vasander, M. Galka, A. Mickiewicz, H. Disbrey, J. Liepins, L. Holmström, and H. Seppä and. Integrating fire-scar, charcoal and fungal spore data to study fire-events in the boreal forest of northern Europe. The Holocene, 29(9):1480-1490, 2019. Available on-line at https://doi.org/ 10.1177/0959683619854524.
- M. Chevalier et al. Pollen-based climate reconstruction techniques for late Quaternary studies. Earth-Science Reviews, 210:103384, 2020. Available on-line at https://doi.org/10.1016/j.earscirev.2020.103384.
- L. Ilvonen, J. Antonio López-Sáez, L. Holmström, F. Alba-Sánchez, S. Pérez-Díaz, J. S. Carrión, M. J. Ramos-Román, J. Camuera, G. Jiménez-Moreno, L. Ruha, and H. Seppä. Spatial and temporal patterns of Holocene precipitation change in the Iberian Peninsula. Boreas, 51(4):776-792, 2022. Available on-line at https://onlinelibrary.wiley.com/doi/abs/ 10.1111/bor.12586.