Data Quality Assessment and the Long-Term Trend of Ground Solar Radiation in China

Abstract

Preliminary schematics of polarimetric signatures at low levels in southern plains classic supercells are developed for pretornado, tornado, and tornado demise times from a small collection of cases, most of which are cyclic tornado producers. Characteristic signatures and patterns are identified for the reflectivity factor (Z HH ), the differential reflectivity (Z DR ), the correlation coefficient ( hv ), and the specific differential phase (K DP ). Signatures likely related to an ongoing tornado are also discussed. Major findings in Z HH at tornado times include "wings" of higher values often extending away from the updraft region, a stronger gradient on the west side of the echo appendage, and a local maximum at the storm location favorable for tornadogenesis. Increasing cyclonic curvature of the hook-echo region was noted through the tornado life cycle. The Z DR tended to indicate hail shafts most commonly at tornado times, with the highest storm values typically located along the storm's forward flank throughout the tornado life cycle. A Z DR minimum often occurred at the tornado-favorable location, while low Z DR occasionally trailed the tornado region. Stormminimum hv typically occurred at the tornado-favorable location at tornado times and in hail shafts or heavy rain areas at other times. Another region of low correlation was the storm updraft, while the highest storm correlation was typically found in the downwind light-precipitation shield. The K DP typically exhibited a storm-core temporal maximum at tornado times, with the highest storm values in regions of hail and heavy rain and the lowest values in the downwind light-precipitation region. Values in the tornadofavorable region were typically near zero and sometimes strongly negative.

Contribution of solar radiation to decadal temperature variability over land

“…In Asia, DTR substantially decreased from the 1950s to the 1980s, was stable until 2000, and then decreased again, consistent with R s derived from sunshine duration (25) and the dimming of directly measured R s between 1960 and 1990 in China (11,31). As already mentioned, after the 1990s, direct observations of R s became inconsistent with those of DTR and sunshine (31), a result of the urban bias of R s observations.…”

Estimating global solar radiation using a hybrid parametric model from MODIS data over the Tibetan Plateau

“…The calibration process is traceable to the World Radiometric Reference. After 1990, the errors of the pyranometers do not exceed 5% (Shi et al, 2008). In this study, measured data from January 1, 2007 to December 31, 2007 were used to evaluate the model.…”

“…However, this criterion is too simple to meet the application demand , especially the DSSR model validation. There are some obviously systematic and operational errors for the four stations (Shiquanhe, Naqu, Geer and Lhasa) in Tibet (Shi et al, 2008;Tang et al, 2010). Therefore, the observed data in Naqu, Geer and Lhasa were excluded and the rest 8 stations were used for validation.…”

“…Therefore, the observed data in Naqu, Geer and Lhasa were excluded and the rest 8 stations were used for validation. Furthermore, three procedures of quality check (QC) from Shi et al (2008) and Tang et al (2010) were used to assess the data quality of the rest 8 stations and some potentially questionable data were excluded.…”

“…QC3: the sunshine duration test from Shi et al (2008) was used to exclude the data that failed the quality check.…”