A modeling approach for reconstruction of annual land surface evapotranspiration using palaeoecological data

Abstract

A modeling approach to reconstruct the annual land surface evapotranspiration from palaeoecological data was suggested. It is based on assumption that the actual evapotranspiration is proportional to potential surface evapotranspiration and to some decoupling factor characterizing the surface moisture conditions. It was described in our study as a function of the climate moisture index (CMI). The potential evapotranspiration rate was derived using palaeoecological data about past land use and land cover, forest coverage, plant species composition and mean annual air temperature. The value of unknown decoupling factor was approximated using the results of evapotranspiration measurements at selected FLUXNET experimental sites located in the areas with different (ranged from extremely wet to moderately dry) moisture conditions. Comparisons of modeled evapotranspiration rates with results of the field flux measurements showed their good agreement for various forest, shrubland and grassland ecosystems in different geographical regions.

Peatland initiation in Central European Russia during the Holocene: Effect of climate conditions and fires

“…Peatlands are common in the study areas due to moderately wet surface moisture conditions (Climate Moisture Index, CMI = 0.3–0.4) and the flat surface topography (Novenko et al, 2019; Olchev et al, 2020). Numerous peatlands are situated in former thermokarst depressions that appeared during the Last Glacial Maximum and in river floodplains (Ivanov, 1995).…”

A New Climate Nowcasting Tool Based on Paleoclimatic Data

“…To describe the surface wetness, we used in our study three key parameters: (i) the water table depth (WTD) in relation to the surface (i.e., the depth of water below the bog surface), which was reconstructed based on the community structure of the subfossil testate amoeba assemblages, using the transfer function developed by Tsyganov et al [20]; (ii) the peat humification estimated as absorption of alkaline extract that directly reflects the moisture in which the peat was formed [21]; (iii) the Climate Moisture Index (CMI) suggested by Willmott and Feddema [22] and the Aridity Index obtained using pollen-based reconstructions of the mean annual temperature and precipitation which allows the classification of moisture conditions as the ratio between available annual precipitation and potential land surface evapotranspiration [15,23].…”