Evaluation of the Reanalysis Surface Incident Shortwave Radiation Products from NCEP, ECMWF, GSFC, and JMA Using Satellite and Surface Observations

Xiaotong Zhang,Shunlin Liang,Yunjun Yao,Guoxin Wang,Bo Jiang,Jie Cheng

doi:10.3390/rs8030225

Abstract

Solar radiation incident at the Earth’s surface (Rs) is an essential component of the total energy exchange between the atmosphere and the surface. Reanalysis data have been widely used, but a comprehensive validation using surface measurements is still highly needed. In this study, we evaluated the Rs estimates from six current representative global reanalyses (NCEP–NCAR, NCEP-DOE; CFSR; ERA-Interim; MERRA; and JRA-55) using surface measurements from different observation networks [GEBA; BSRN; GC-NET; Buoy; and CMA] (674 sites in total) and the Earth’s Radiant Energy System (CERES) EBAF product from 2001 to 2009. The global mean biases between the reanalysis Rs and surface measurements at all sites ranged from 11.25 W/m2 to 49.80 W/m2. Comparing with the CERES-EBAF Rs product, all the reanalyses overestimate Rs, except for ERA-Interim, with the biases ranging from −2.98 W/m2 to 21.97 W/m2 over the globe. It was also found that the biases of cloud fraction (CF) in the reanalyses caused the overestimation of Rs. After removing the averaged bias of CERES-EBAF, weighted by the area of the latitudinal band, a global annual mean Rs values of 184.6 W/m2, 180.0 W/m2, and 182.9 W/m2 were obtained over land, ocean, and the globe, respectively.

Highlights

Solar radiation incident at the Earth’s surface (Rs ) is one essential component of the total energy exchange between the atmosphere and the Earth’s surface
Rs products were projected onto a 1 ̋ spatial resolution using a bilinear interpolation of a weighted average of pixels in the nearest 2-by-2 neighborhood to match that of the CERES-EBAF (Ed2.7) Rs data
The current study presents the validation and the inter-comparison of Rs estimates provided by the current representative from six current representative global reanalyses (NCEP–NCAR, National Centers for Environmental Prediction (NCEP)-DOE, CFSR; ERA-Interim; MERRA; and JRA-55) using the quality-controlled surface measurements at 674 sites from five different observational networks including GEBA, Baseline Surface Radiation Network (BSRN), Greenland Climate Network (GC-NET), Buoy, and CMA of 2001–2009

Summary

Introduction

Solar radiation incident at the Earth’s surface (Rs ) is one essential component of the total energy exchange between the atmosphere and the Earth’s surface. Worldwide monitoring of Rs from ground-based stations began in the late 1950s [1]. It is still insufficient to derive the global radiation distribution from ground measurements alone due to the sparsity and heterogeneity of stations [2,3,4]. Observational measurements provide the best estimate of the state of Rs where they are taken. A number of gridded global Rs products exist from remote sensing [2,5,6,7] and reanalysis [8,9,10,11,12]. Satellite remote sensing is one of the most practical ways to derive Rs with relatively higher spatial resolution and accuracy, but the temporal coverage is always limited

Results

Discussion

Conclusion