Tibetan Plateau precipitation as depicted by gauge observations, reanalyses and satellite retrievals

Abstract

The European Centre for Medium-range Weather Forecasts (ECMWF) reanalysis ERA-40, ERA-Interim, University of Washington (UW) data, APHRODITE's Water Resources (APHRODITE), and Tropical Rainfall Measuring Mission (TRMM) Multisatellite Precipitation Analysis (TMPA) precipitation estimates are compared with each other and with the corrected gauge observations over the Tibetan Plateau (TP) at both basin and plateau scales. The ERA-40 generally can capture the broad spatial and temporal distributions in the gauge-based precipitation estimates over the TP. However, the ERA-40 shows little agreement with the gauge-based precipitation in annual variations for the years before 1979. The anticipated improvements in the ERA-Interim precipitation relative to ERA-40 have not been realized in this study. It greatly overestimates the Corrected-China Meteorological Administration (CMA) (by 74-290%) and other datasets, although the ERA-Interim has a better correspondence than ERA-40 with the Corrected-CMA data at both annual and monthly scales among the selected basins. All the products can detect the large-scale precipitation regime, including the monsoon-dominated precipitation in summer and the westerly-wind-induced precipitation in winter. The Corrected-CMA and APHRODITE estimates generally show decreasing trends in summer and increasing trends in spring and winter precipitation during 1961-2007 at both basin and plateau scales. However, the Corrected-CMA shows larger values in trends and more cases with significance than the APHRODITE, suggesting the effects of the undercatch corrections on the precipitation trends. The use of precipitation derived from current reanalysis projects is less preferable for hydrology analysis than the TP observational data at basin scales. However, using gauge-based precipitation datasets as hydrologic model forcings should be careful in the river basins where gauge station network is spare, such as in the Yarlung zangbo river basin. Satellite products still hold a great potential for providing high-resolution precipitation information in remote regions such as the western TP, although more evaluations are needed on the feasibility of satellite precipitation products on the TP where the topography is complex and rainfall rate is highly variable.

Spatial-Temporal Patterns and Controls of Evapotranspiration across the Tibetan Plateau (2000–2012)

“…The change of ET was positive in the edge area, except at the northern and southeastern edge of the Tibetan Plateau. ET increased in this region, partly due to the increase in precipitation [50,[56][57][58]. However, ET decreased in the middle part of the Tibetan Plateau, including almost all of Tibet.…”

Evaluation of Five Satellite-Based Precipitation Products in Two Gauge-Scarce Basins on the Tibetan Plateau

“…The TP, known as the "third pole", has an average elevation of over 4000 m above sea level (a.s.l) [42]. The TP is also the source of many Asian rivers, such as the Yellow River, the Yangtze River, and the Mekong River, supporting hundreds of millions of people living downstream [43].…”

Similarity and Error Intercomparison of the GPM and Its Predecessor-TRMM Multisatellite Precipitation Analysis Using the Best Available Hourly Gauge Network over the Tibetan Plateau

“…However, accurate observation of precipitation is challenging in many remote regions of the world, such as the Tibetan Plateau (TP), due to sparse gauge networks and high spatial variability in precipitation [1,2]. Satellite remote sensing has provided unprecedented precipitation information at a broader range of time and space scales, representing a significant contribution toward mapping global rainfall [3][4][5].…”

“…Efforts have been made to assess the suitability of satellite precipitation products over the TP [1,[7][8][9][10][11]. Previous studies found that the TMPA precipitation products outperform other satellite products (e.g., PERSIANN and CMORPH) across the plateau with lower errors and biases [9,11].…”