The precipitation climate of Central Asia—intercomparison of observational and numerical data sources in a remote semiarid region

Abstract

ABSTRACT:In this study, we systematically compare a wide range of observational and numerical precipitation datasets for Central Asia. Data considered include two re-analyses, three datasets based on direct observations, and the output of a regional climate model simulation driven by a global re-analysis. These are validated and intercompared with respect to their ability to represent the Central Asian precipitation climate. In each of the datasets, we consider the mean spatial distribution and the seasonal cycle of precipitation, the amplitude of interannual variability, the representation of individual yearly anomalies, the precipitation sensitivity (i.e. the response to wet and dry conditions), and the temporal homogeneity of precipitation. Additionally, we carried out part of these analyses for datasets available in real time. The mutual agreement between the observations is used as an indication of how far these data can be used for validating precipitation data from other sources. In particular, we show that the observations usually agree qualitatively on anomalies in individual years while it is not always possible to use them for the quantitative validation of the amplitude of interannual variability. The regional climate model is capable of improving the spatial distribution of precipitation. At the same time, it strongly underestimates summer precipitation and its variability, while interannual variations are well represented during the other seasons, in particular in the Central Asian mountains during winter and spring.

Glacier and runoff changes in the Rukhk catchment, upper Amu-Darya basin until 2050

“…Irkht offers a valuable long-term series (since 1939) from this strongly continental mountain region. Mean monthly temperatures range from − 13.6°C in January to 14.4°C in July, the resulting inter-annual amplitude is 28 K. Precipitation is very low due to the leeward location with respect to the Central Pamir (Schiemann et al, 2008). Mean annual sums in the five years of discharge observations are only 139 mm, 72% of which occur from December to May, mostly in solid form.…”

“…Reanalysis data are an important source of precipitation estimates in areas with few observations and have also been used in Central Asia before (e.g. Schär et al, 2004;Schiemann et al, 2008). A gridded (0.25°) precipitation dataset for Asia was constructed from interpolated observations within the APHRODITE project (Asian Precipitation -Highly-Resolved Observational Data Integration Towards Evaluation of the Water Resources).…”

Re-establishing glacier monitoring in Kyrgyzstan and Uzbekistan, Central Asia

“…These two stations were equipped with standard meteorological and ground sensors (see detailed description in Schöne et al, 2013 Salzmann et al, 2013;Schär et al, 2004;Schienmann et al, 2008;Schmidli et al, 2001). …”

A statistically based seasonal precipitation forecast model with automatic predictor selection and its application to central and south Asia

“…Bothe et al (2011) demonstrated that drought and moist winter seasons over central Asia are dominated by different wave patterns over the Eurasian sector and particularly mention the NAO and the East Atlantic pattern (EA) (which represent the first two modes of SLP variability in the North Atlantic domain) as important covariates. Schiemann et al (2008) reported that an anomalous location or a decreasing strength of the westerly jet stream result in drought conditions over parts of central Asia due to modified tracks and intensities of westerly disturbances. Dimri (2013) found that a distinct southward shift of the westerly jet stream is associated with wet winter conditions over the Himalayas.…”