In the preceding studies by many authors, in particular they found that moist processes were responsible for the strong initial error growth in meso-scale. In the present study they take a more systematic look at the processes by means of the initial introduced mall errors and found that the errors first grow as small-scale differences associated with moist convection, then spread upscale as their growth begin to slow. In the context, we use vastly different initial perturbation methodologies to investigate the initial error growth in the storm scale with open boundary conditions. Comparison of
the perturbation methodologies indicates that the ensuing patterns of ensemble spread converge within only a few minutes, irrespective of the initial perturbations employed. In the vertical direction, the largest errors in different variable fields concentrated in different layers (e.g., the largest errors in the temperature field concentrated in the upper tropopause, but in the horizontal wind field, the largest errors converged in the troposphere.). The error growth in the first and middle time contact with the storm tightly, but at last, the error growth goes their ways very slow and flat. The
growth of the uncertainties is limited by the saturation effects, which in turn is controlled by the larger-scale atmospheric
environment.
KEYWORDS: Temperature metrology, Climate change, Meteorology, Data modeling, Climatology, Information science, Information technology, Analytical research, Systems modeling, Environmental sensing
Variation of winter and summer temperature in China were discussed in detail by using EOF analysis and
differences between the datasets derived from in situ stations of china meteorological data sharing service system and
NECP/NCAR reanalysis, ERA40 reanalysis were compared in winter and summer temperature in China. Results showed
that: 1) Winter temperature increases linearly with identical signs all over china except the Tibetan plateau. It is colder
than the normal before the late 1970s and warmer since then, especially in 1990s.2) Variation of summer temperature is
complicated that it increases in north China but decreases in south to mid-lower reaches of Huanghe and the north of
Jiangnan district; 3) The values of NCEP/NCAR and ERA40 reanalysis data are commonly lower than the observations
in winter and higher in summer; meanwhile, the change ranges of the reanalysis are closer to the observations'. The
spatial and temporal features of winter temperature obtained from the reanalysis data are consistent with that of the
observations, but for summer temperature, the spatial and temporal features derived from the ERA40 are better than that
of NCEP/NCAR. ERA40 can represent main variations of the summer temperature as the spatial distributions, linear
trend and inter-decadal characteristics, but the NCEP/NCAR dataset shows significant differences from the observations
for the spatial/temporal variations, the remarkable abrupt change around mid-1970s in NCEP/NCAR can not be seen in
observations and in ERA40.
Since the summer rainfall over Yangtze River and Huaihe River often leads to the occurrence of floods, with inconsistent distribution among those years, it is important to investigate the characteristics and the causes of rainfall anomalies. Therefore, REOF analysis is performed on 1951-1998 monthly mean precipitation from both CMA (China Meteorological Administration)-provided 160 weather stations and NCEP/NCAR re-analyses. Results show that: 1) summer rainfall over the mid-lower reaches of Yangtze River (MLRYR) can be divided into two rain belts in the south and north of the study region, called as the southern and northern branch of rain belt, respectively. In detail, the southern belt is located in south of the MLRYR, i.e. regions of Jiangxi, Hunan and Zhejiang, and the other is located in regions of Chongqing, southeast Shaanxi, Hubei, south Henan and Anhui, with east-west zonal distributions for the both; 2) both the rain belts are marked by conspicuous intra-annual and inter-decadal oscillations, with remarkable 14-/8-yr periods on the inter-decadal scale for the southern/northern belt. Besides, two belts are different in the amount of precipitation during the same stage, which is closely related to the large-scale circulation, especially the strength of summer monsoon and subtropical high, both impacting greatly on amount and distribution of the precipitation in two belts.
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