Evaluation of six gauge-based gridded climate products for analyzing long-term historical precipitation patterns across the Lancang-Mekong River Basin

Abstract

Freshwater plays a vital role in global sustainability by improving human lives and protecting nature. In the Lancang-Mekong River Basin (LMRB), sustainable development is principally dependent upon precipitation that predominantly controls freshwater resources availability required for both life and livelihood of ∼70 million people. Hence, this study comprehensively analyzed long-term historical precipitation patterns (in terms of trends, variability, and links to climate teleconnections) throughout the LMRB as well as its upper (Lancang River Basin, LRB) and lower (Mekong River Basin, MRB) parts employing six gauge-based gridded climate products: Asian Precipitation Highly-Resolved Observational Data Integration Towards Evaluation of Water Resources (APHRODITE), Climate Prediction Center (CPC), Climate Research Unit (CRU), Global Precipitation Climatology Center (GPCC), Precipitation Reconstruction over Land (PRECL), and University of Delaware (UDEL). Accordingly, annual and seasonal (dry and wet) precipitation time series were calculated for three study periods: century-long outlook (1901-2010), mid-past (1951-2010), and recent decades (1981-2010). However, the role of climate teleconnections in precipitation variability over the LMRB was only identified during their available temporal coverages: mid-past and recent decades. The results generally showed that: (i) both annual and seasonal precipitation increased across all three basins in 1981-2010; (ii) wet and dry seasons got drier and wetter, respectively, in all basins in 1951-2010; (iii) all such changes were fundamentally attributed to increases in precipitation variability on both annual and seasonal scales over time; (iv) these variations were most strongly associated with the Pacific Decadal Oscillation (PDO), Atlantic Multi-decadal Oscillation (AMO) and East Pacific/North Pacific (EP/NP) pattern in the LMRB and the MRB during 1951-2010, but with the North Sea-Caspian Pattern (NCP) and the Southern Annular Mode (SAM) in the LRB; (v) such relationships got stronger in 1981-2010, while the Southern Oscillation Index (SOI) became the most influential teleconnection for dry season precipitation variability across all basins; and (vi) GPCC (APHRODITE) provided the most reliable gauge-based gridded precipitation time series over the LMRB for the years before (after) 1951. These findings lay a foundation for further studies focusing on water resources and sustainable development in the LMRB.