Temperature change in the Tianshan Mountains and its external drivers

Abstract

The Tianshan Mountains area (TMA), located in east Central Asia, has experienced faster temperature rise than the global average rate from the 1960s to the present. This initial estimate is carefully examined using a new dataset of high spatial resolution dynamically downscaled by an updated Weather Research and Forecasting (WRF) regional model. This dataset and other available climate data products show that the WRF model outputs describe temperature changes in TMA consistent with limited available observations (R2 = 0.95 and RMSE = 3.25 °C). The model data confirm that the temperature at TMA has risen at a rate of 0.18 °C/decade, faster than the global mean rate of 0.15 °C/decade. Strong warming rates are also found in spring and summer while the winter is cooling. In addition to revealing these variations of TAM temperatures the model outputs provide high resolution meteorological and climatic data and open the opportunity for studying surface hydrology and ecosystem responses in the region. Possible forcings of the changes of TMA temperature are explored from a global perspective using a set of ten climate indices. Results show that the most impactful processes on TMA temperatures are those associated with the contraction of the arctic sea-ice in recent decades, SST anomalies in the tropical Pacific, e.g., ENSO, SST variations in both the tropical Atlantic and North Atlantic Ocean. The east Asian jet stream also shows a significant impact on TMA temperatures likely by its impact on placing its entrance region over the Central Asia and thus weather disturbances in TMA.