Distribution and Variation of the Surface Sensible Heat Flux Over the Central and Eastern Tibetan Plateau: Comparison of Station Observations and Multireanalysis Products

Abstract

Surface sensible heat fluxes (SH) over Tibetan Plateau (TP) dictate the seasonal conversion, onset and maintenance of the Asian monsoon. Spatiotemproal variability in SH over central and eastern TP (CETP) from reanalysis products (i.e., JRA55, ERA‐Interim, NCEP1, and NCEP2) and derived using bulk transfer approximations applied to observations is characterized for all seasons during 1980–2015 and is diagnosed in the context of two important drivers of variability: wind speed and land‐air temperature difference (Tg‐Ta). In the climatological mean, SH from observations increases from east to west and exhibits obvious seasonality with highest value in spring and lowest in winter. Declines in SH prior to 2000 as manifest in the observations appears to have resulted from changes in wind speeds, and the subsequent recovery is attributable to increases in both wind speeds and air‐surface temperature gradients. The intercomparison shows that ERA‐Interim exhibits greatest accord with observations in terms of the climatological distribution and seasonality, and all reanalyses exhibit some aspects of the temporal variability and long‐term trends as manifest in the observations. However, the root causes of the long‐term variability in SH as manifest in the reanalysis products are not consistent with inferences derived from the observations.

Precursor Effect of the Tibetan Plateau Heating Anomaly on the Seasonal March of the East Asian Summer Monsoon Precipitation

“…As a result of limited observations and the nonuniform distribution of routine meteorological monitoring stations over the Tibetan Plateau, it is still challenging to accurately estimate diabatic heating in this region, although the TPSH in this work is generally consistent with that calculated by Chen, Pryor, et al (2019) in terms of intensity and variation.…”

Impact of North Atlantic SST and Tibetan Plateau forcing on seasonal transition of springtime South Asian monsoon circulation

“…Surface SH over the TP is the dominant source of diabatic heating and reaches its maximum during the boreal spring (Yeh and Gao 1979;Liu et al 2015;Duan et al 2017;Zhao et al 2018;Chen et al 2019). The positive surface SH anomaly over the TP generates negative vorticity anomaly at higher levels, which influences the atmospheric circulation across the northern hemisphere by triggering Rossby wave trains (Wu et al 1996(Wu et al , 2015Liu et al 2017).…”

A climatology of surface–air temperature difference over the Tibetan Plateau: Results from multi‐source reanalyses

“…Moreover, Δ T time series of the reanalyses exhibit large fluctuations in DJF and MAM, indicating large year‐to‐year variability. Similar decreasing trends are also reported by NCEP reanalysis data (Chen et al ., 2019). Taken together, the median Δ T has decreased significantly in four seasons from 1979 to 2018 (Table S2), in accord with the decline of SHF (Wang et al ., 2013; Duan et al ., 2018) and the reduction of heating ability in recent decades (Yang et al ., 2011).…”

“…For instance, MERRA has a high correlation with observations of surface meteorological variables (Wang and Zeng, 2012). ERA‐Interim data shows relatively small cold bias in T a (Wang et al ., 2017) and better performance in water cycle (Wang and Zeng, 2012), as well as SHF on the TP (Chen et al ., 2019).…”