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Based on the 1961-2007 ground surface meteorological data from 558 meteorological stations in China, this paper analyzed the differences of agricultural climate resources in China different regions, and compared the change characteristics of the agricultural climate resources in 1961-1980 (period I) and 1981-2007 (period II), taking the year 1981 as the time node. As compared with period I, the mean annual temperature in China in period II increased by 0.6 degrees C, and the > or = 0 degrees C active accumulated temperature in the growth periods of chimonophilous crops and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased averagely by 123.3 degrees C x d and 125.9 degrees C x d, respectively. In 1961-2007, the mean annual temperature increased most in Northeast China, and the > or = 10 degrees C active accumulated temperature in the growth periods of thermophilic crops increased most in South China. The whole year sunshine hours and the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops in period II decreased by 125.7 h, 32.2 h, and 53.6 h, respectively, compared with those in period I. In 1961-2007, the annual sunshine hours decreased most in the middle and lower reaches of Yangtze River, while the sunshine hours in the growth periods of chimonophilous crops and of thermophilic crops decreased most in North China and South China, respectively. In the whole year and in the growth periods of chimonophilous and thermophilic crops, both the precipitation and the reference crop evapotranspiration in this country all showed a decreasing trend, with the largest decrement in the precipitation in the whole year and in the growth periods of chimonophilous and thermophilic crops in North China, the largest decrement in the reference crop evapotranspiration in the whole year and in the growth periods of thermophilic crops in the middle and lower reaches of Yangtze River, and the largest decrement in the reference crop evapotranspiration in the growth periods of chimonophilous crops in Northwest China. In 1961-2007, the climate in China in the whole year and in the growth periods of thermophilic crops showed an overall tendency of warm and dry, and the climate in the growth periods of thermophilic crops became warm and dry in Southwest China, North China, and Northeast China, but warm and wet in the middle and lower reaches of Yangtze River, Northwest China, and South China, whereas the climate in the growth periods of chimonophilous crops became warm and dry in North China, but became warm and wet in Northwest China.

Based on the 1961-2007 observation data from 66 meteorological stations in the sub-humid and warm-temperate irrigated wheat-maize agricultural area of Huang-Huai-Hai Plain, this paper analyzed the spatiotemporal change characteristics of agro-climate resources for chimonophilous and thermophilic crops in the area in 1961-1980 and 1981-2007. The analyzed items included the length of temperature-defined growth season and the active accumulative temperature, sunshine hours, precipitation, reference evapotranspiration, and aridity index during the temperature-defined growth season. With climate warming, the length of temperature-defined growth season of chimonophilous and thermophilic crops in the area in 1981-2007 extended by 7. 4 d and 6. 9 d, and the > or = 0 degrees C and > or = 10 degrees C accumulative temperature increased at a rate of 4.0-137.0 and 1.0-142.0 degrees C d (10 a)(-1), respectively, compared with those in 1961-1980. The sunshine hours during the temperature-defined growth season of the crops decreased markedly; and the precipitation during the temperature-defined growing season decreased in most parts of the area, being obvious in Hebei and north Shandong Province, but increased in north Anhui and southeast Henan Province. In most parts of the area, the reference evapotranspiration of chimonophilous and thermophilic crops during their temperature-defined growth season decreased, and the aridity index increased.

By using the 1961-2007 daily weather data from 78 meteorological stations in Northwest Arid Area, this paper analyzed the spatiotemporal characteristics of agricultural climate resources, i.e., heat, light, and precipitation, in the area, both in the whole year and in temperature-defined growth seasons of chimonophilous and thermophilic crops. In 1961-2007, the mean annual temperature in the area had an increasing trend, and the climate tendency rate was 0.35 degrees C x (10 a)(-1). The accumulated temperature in temperature-defined growth seasons of both chimonophilous and thermophilic crops also had an increasing trend, and the climate tendency rate was 67 and 50 degrees C d x (10 a)(-1), respectively. The annual sunshine hours in most stations of the research area had an obvious decreasing trend, but the sunshine hours during the temperature-defined growth seasons of chimonophilous and thermophilic crops had an increasing trend, except that in most regions of Xin-jiang and east Ningxia Plain. The annual reference evapotranspiration in most regions of the study area tended to decrease, while the reference evapotranspiration during temperature-defined growth seasons of chimonophilous and thermophilic crops tended to decrease in the west but increase in the east. Compared with that in 1961-1980, the precipitation both in the whole year and in temperature-defined growth seasons of chimonophilous and thermophilic crops in 1981-2007 increased, and the increment reduced progressively from the northwest to the southeast.

Based on the 1961-2007 ground observation data from 88 meteorological stations in Southwest China, and by using statistical methods and GIS software, this paper analyzed the spatiotemporal change characteristics of agricultural climate resources in this region in the whole year and during temperature-defined growth period. In 1961-2007, the annual mean temperature in the region showed an increasing trend, with the increment averaged 0.18 degrees C x (10 a)(-1). The > or = 10 degrees C and > or = 15 degrees C accumulated temperature during temperature-defined growth period also showed an increasing trend, with the increment averaged 55.3 degrees C x d x (10 a)(-1) and 37 degrees C x d x (10 a)(-1), respectively. The annual sunshine hours decreased gradually from west to east, and the decreasing trend was more significant in eastern than in western region. The sunshine hours during temperature-defined growth period showed an overall increasing trend, and the spatial difference was great. The precipitation resource had an overall decrease, with the decrement in whole year and during temperature-defined growth period averaged 10 mm x (10 a)(-1) and 8 mm x (10 a)(-1), respectively. The annual reference crop evapotranspiration generally decreased, but the decrement was less than that of annual precipitation. The reference crop evapotranspiration during temperature-defined growth period within about 53% meteorological stations decreased.

The period 1961-2007 was divided into two by the time node of year 1981, and the change characteristics of the agricultural climate resources both in period I (1961-1980) and in period II (1981-2007) were analyzed and compared. The results showed that under the background of global warming, the average climatic trend rate of > or = 10 degrees C accumulated temperature in the middle and lower reaches of Yangtze River in temperature-defined growth season during 1961-2007 was 74 degrees C x d x 10 a(-1), and the > or =10 degrees C accumulated temperature in period II was 124 d higher than that in period I. Comparing with that in period I, the safe planting boundary of double cropping rice in period II moved 0.79 degrees northward. In 1961-2007, the precipitation in temperature-defined growth season had an overall increasing trend. Comparing with those in period I, the precipitation and the area of > or = 767 mm precipitation (water requirement for normal growth of double cropping rice) in period II were increased by 1.6% and 1.13 x 10(4) km2, respectively. The average sunshine hour in temperature-defined growth season in period II was reduced by 8.1%, comparing with that in period I. In recent 47 years, about 91.1% stations in the reaches showed a decreasing trend in sunshine hours. Comparing with that in period I, the reference crop evapotranspiration in temperature-defined growth season in period II showed a slightly decreasing trend, and its low value region expanded while its high value region narrowed. The beginning date of daily temperature over 10 degrees C was averagely 2 days earlier in period II than that in period I, while the ending date was in reverse. The ending date of daily temperature over 22 degrees C was almost the same in periods I and II.

By using the 1961-2007 daily weather data from 66 meteorological stations all over South China, this paper studied the spatiotemporal change characteristics of agricultural climate resources, including heat, light, and precipitation, in this region on the scales of whole year and temperature-defined growth season. In 1961-2007, the mean annual air temperature in this region tended to be increased by 0.20 degrees C x (10 a)(-1), and the climatic trend of > or = 10 degrees C accumulated temperature in temperature-defined growth season increased gradually from north to south, with an average of 98 degrees C x d x (10 a)(-1). Comparied with those in 1961-1980, the areas of the accumulated temperature zone of 6200-7500 degrees C x d and 7500-8000 degrees C x d in 1981-2007 increased by 1.5 x 10(4) and 4.7 x 10(4) km2, respectively. In 1961-2007, the sunshine hours on the scales of whole year and temperature-defined growth season decreased by -57 h x (10 a)(-1) and -38 h x (10 a)(-1), respectively, and the areas with sunshine hour > or = 1800 h on the two scales tended to be decreased, compared with those in 1961-1980. The precipitation on the two scales increased slightly, and the increment varied obviously in different parts of the region. There were 62% and 52% of the stations where the reference crop evapotranspiration on the scales of whole year and temperature-defined growth season was in negative, respectively. In 1981-2007, the high-value area of reference crop evapotranspiration decreased, while the low-value area increased, compared with those in 1961-1980. The mean climatic trend of annual humidity index was 0.01 x (10 a)(-1), and 70% of the stations showed an increasing trend. Comparing with that in 1961-1980, the humidity index on the scale of temperature-defined growth season in 1981-2007 was increased by 0. 02, with 53% of the stations showed positive. On the whole, the change characteristics of climate in South China in 1961-2007 showed a tendency of warming and wetting, which would impact the cropping system, yield, and agricultural structure in the region.

Based on the 1959-2007 observation data of daily mean temperature from 19 meteorological stations in Guizhou Province, and combining with the late spring cold (LSC) intensity index and disaster grade division standard, this paper analyzed the spatiotemporal evolution characteristics of LSC, including LSC occurrence frequency, ratio of LSC-occurring stations to all stations, decadal variation, abrupt climate change, and periodic variation, in the province. In 1959-2007, the occurrence frequency of no LSC in the province was the highest, followed by serious LSC, and that of medium and slight LSC was approximately the same. Under the background of global warming, the ratio of medium LSC-occurring stations to all stations had the most obvious variation, with the climatic trend reached 1.4% x (10 a)(-1), while the ratios of no LSC-, slight LSC-, and serious LSC- occurring stations all showed an appreciably decreasing trend. The LSC intensity in the province was the highest in the 1990s, followed by in the 1980s, 1960s, 1970s, and 2000-2007. In the province, the LSC intensity showed an increasing trend in west and northwest high altitude areas, central area, and north area, but an appreciably decreasing trend in east and south areas. In the west, northwest, north, and central areas of the province, LSC intensity had a mutation from low to high in 1975. The LSC in the province had an obvious periodical variation, with the inter-annual period being mainly 2-4 years, and the decadal periods being mainly 13 - 15 years and 27-29 years.

Based on the 1961-2007 weather data from 72 meteorological stations in three provinces of Northeast China, the change characteristics of agricultural climatic factors including yearly and temperature-defined growing season's mean air temperature, > or =10 degrees C accumulated temperature, precipitation, reference evapotranspiration, and sunshine hours were analyzed. In 1961-2007, the yearly mean air temperature in the three provinces had an increasing trend, with a rate of 0.38 degrees C x 10 a(-1). The > or =10 degrees C accumulated temperature in temperature-defined growing season also had an increasing trend, and the border of > or =10 degrees C accumulated temperature belt moved northward and eastward. The area of > or =3200 degrees C x d accumulated temperature increased by 2.2 x 10(4) km2. The belt of 2800-3200 degrees C x d moved northward about 0.85 degrees and eastward about 0.67 degrees, while that of 2400-2800 degrees C x d moved northward about 1.1 degrees. The sunshine hours decreased significantly, especially in the east part of Songnen Plain, central and west plains of Jilin Province, and west part of Liaohe River Plain. The area with sunshine hours > 2800 h decreased from 13.6 x 10(4) km2 to 4. 1 x 10(4) km2, and the zone with sunshine hours 2600-2800 h moved westward about 1.5 degrees. The average sunshine hour in temperature-defined growing season was 1174 h. Comparing with that in 1961-1980, the region with more sunshine hours in temperature-defined growing season in 1981-2007 narrowed significantly, and the zone with sunshine hours 1200-1400 h moved westward about 0.9 degrees. In 1961-2007, both the yearly and the temperature-defined growing season's precipitation decreased, and the yearly reference evapotranspiration increased in Heilongjiang Province and in the eastern mountain areas of Jilin Province but decreased in the central and west plains of Jilin Province and in Liaoning Province. Comparing with that in 1961-1980, the zone of reference evapotranspiration with the value of > or =900 mm in 1981-2007 moved westward about 1 degree, and the reference evapotranspiration in temperature-defined growing season increased in most regions of Heilongjiang and Jilin Province but decreased in a rate of 0-14 mm x 10 a(-1) in most regions of Liaoning Province.