Moreover, not all meteorological variables (in particular, such elements of the land water cycle as evaporation, soil moisture, and moisture fluxes into the soil) are simulated with sufficient

reliability (IPCC 2007). Thus, for example, the Fourth Assessment Report of the Intergovernmental Panel on Climate Change notes that ‘evaporation fields from the ERA-40 and NRA are not considered reliable because they are not well constrained by precipitation and radiation’. For this reason, the direct use of in situ data for model results validation is more reliable. Moreover, such data are already available for analysis. The Global Soil Moisture Bank (http://climate.envsci.rutgers.edu/soil/_moisture/) (Robock et al. 2000) exists, Ceritinib concentration where data on in situ records of soil moisture have been gathered for Russia, Ukraine, USA, China, Mongolia, Brazil and some other countries for more than 30 years. Pan evaporation is measured worldwide. In some countries (e.g. Russia and the United States) the time series of this variable span more than 40–50 years. It seems appropriate

to set up a World Centre for the accumulation of pan evaporation data (as well as lysimeter data used for monitoring actual evaporation) to make them available to the scientific community (similar to the Global Selleckchem Lenvatinib Soil Moisture Bank). The value of this information has already been tested in climatic change assessments (see Golubev et al. 2001). These variables are not simulated in the reanalyses: soil moisture, potential evaporation and evapotransporation are the most important elements of the terrestrial water cycle. Furthermore, soil moisture characterizes the amount of water accumulating within the active (1 m) soil layer, pan evaporation can be accepted as a potential evaporation estimate, LY294002 and lysimeter measurements from natural surfaces (unfortunately, from a very sparse network) can be used as estimates of evapotranspiration. This paper assesses the changes in the first two characteristics – soil moisture and pan evaporation – as recorded by the network of long-term meteorological stations of the former USSR and subsequently of the Russian Federation, Belarus and the Baltic

States. Quite a large area of the drainage basin of the Baltic Sea lies in Russian territory. Soil moisture observations (from the 1970s to 2000/2001) are currently available from 14 long-term stations in this region. As far as pan evaporation is concerned, there are 4 stations in Russia with observations from the 1950s to 2008 and 8 stations in the former Soviet republics with observations from the 1950s to the mid-1990s; these data are used in this analysis (Figure 1). Soil moisture data are represented by 10-day observations on soil plots with natural (mostly meadows) vegetation and on fields with winter crops during the warm period (from April to August/September). In the cold season, these observations are made on the 18th or 28th day of each month.