Long-term Variation of Precipitation around Lake Balkhash in Central Asia from the End of the 19th Century

Abstract

The long-term variation of precipitation around Lake Balkhash since 1872 was studied. CDIAC TR051 (1872-1989 in the study area) was compared with GHCN Gridded Precipitation Products (1900-2007, GHCN_GRD) and CRU TS2.1 (1901-2002), the latter two being used in IPCC AR4 for assessing the global annual land precipitation anomalies in the 20th century. From 1901 to 1989, these datasets had no statistically significant differences, and exhibited similar variations. CDIAC TR051 was, therefore, combined with GHCN_GRD for 1925 without any inhomogeneities found in the combined time series.Around Lake Balkhash, negative precipitation anomalies prevailed from 1872 to 1950 with a significant recovery found around 1900. IPCC AR4 indicated that precipitation increased in Central Asia throughout the 20th century, whereas this study clarified that the increasing trend has been presented since 1872 in the study area. Moreover, the integral curve of the precipitation anomalies corresponded well with variation of the water level of Lake Balkhash, i.e., negative precipitation anomalies from 1872 onward resulted in the continuous decrease of the water level until 1950. This coincides with other proxy data such as a sediment core of Lake Balkhash dug up in 2007.