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Cao W.,Anhui Meteorological Institute | Cao W.,Anhui Province Atmospheric Science and Satellite Remote Sensing Key Laboratory | Duan C.F.,Anhui Climate Center | Shen S.H.,Nanjing University of Information Science and Technology
Shengtai Xuebao/ Acta Ecologica Sinica | Year: 2015

In the context of global warming, the impact of climate change on water resources is becoming increasingly significant and is thus drawing more attention. As a main component of the hydrological cycle, potential evapotranspiration (ET0) represents the maximum possible evaporation and is the rate of evaporation that would occur under given meteorological conditions from a continuously saturated surface. ET0 is essential for scheduling of irrigation system running times, preparing input data for hydrological models used in water balance studies, and assessing the hydrological impacts of the changing climate. Therefore, the trends of the changes in ET0 and its dominant factors across different regions of the world have been studied by many researchers in recent decades. Despite the global warming, decreasing trends in ET0have been detected in several countries, including the United States, Russia, India, China, Australia, and New Zealand. Decreasing sunshine hours, declining wind speed, and increasing relative humidity have been considered to be the main causes of the decreasing ET0.Analysis of the linear trend of the time series is frequently used in climate change research. The linear trend can reflect the overall trend of climate change over a time period, but it cannot describe the undulating character of climate change over a long time period. Thus, the characteristics of interdecadal turning of climatic factors, including air temperature, precipitation, and solar radiation, have become a topic of concern for many researchers worldwide.Thorough exploration of the interdecadal turning of ET0 trends can lead to a better understanding of the evolution and abrupt changes of ET0 related to climate change. Based on the FAO56 Penman-Monteith equation, interdecadal breakpoints in ET0 trends were studied using Tom- and Miranda’s climate-trend turning discriminatory model for 580 meteorological stations across China during 1971—2010. Differences in the trends and determining factors between the before and after breakpoint periods were also analyzed. The results showed that annual average ET0 decreased significantly (-2.46 mm/ a) before the 1990s but increased significantly (1.57 mm/ a) after the 1990s across China. This phenomenon was closely related to the interdecadal breakpoints in the trends of four meteorological factors affecting ET0 variations. The decrease in ET0 that occurred before the 1990s was attributed to a larger absolute value of the negative contributions caused by decreasing wind speed and sunshine duration compared to that of the positive contribution caused by increasing air temperature. After the 1990s, positive contribution from the air temperature and relative humidity increased due to the more intensive warming and climatic aridity across most of the areas in China and exceeded the smaller absolute value of the negative contribution from the wind speed and sunshine duration, causing the increasing trend in ET0. The interdecadal breakpoints existed at more than 80% of the meteorological stations across China, and there were differences between the pre-and post-breakpoint distribution patterns. Before the 1990s, wind speed and sunshine duration were the determining factors for most stations in North China and South China, respectively. After the 1990s, the number of stations with air temperature or relative humidity as a determining factor increased, especially in Northwest China, the Tibetan Plateau, and some parts of the southeastern coastal area. © 2015 Ecological Society of China. All rights reserved.

Zhang J.,Anhui Meteorological Institute
2nd International Conference on Information Science and Engineering, ICISE2010 - Proceedings | Year: 2010

The temperature suitability, sunlight suitability, precipitation suitability model and climatic suitability model of single-season rice are set up by using Fuzzy mathematics theory and referring to former study, and the temperature suitability, sunlight suitability, precipitation suitability and climatic suitability of different growing periods have been calculated separated with the model and related data during 1960-2009 of Anhui Province. The results show that temperature suitability and sunlight suitability are relatively big, and precipitation suitability is small in Anhui Province. Climatic suitability and temperature suitability of single-season rice have decreasing trend, and the sunlight suitability has a downward trend. © 2010 IEEE.

Wu L.,Chinese Academy of Meteorological Sciences | Huo Z.-G.,Chinese Academy of Meteorological Sciences | Huo Z.-G.,Nanjing University of Information Science and Technology | Yang J.-Y.,Chinese Academy of Meteorological Sciences | And 4 more authors.
Chinese Journal of Ecology | Year: 2016

Stepwise regression prediction models of levels of annual first low temperature disaster to double cropping rice were established based on meteorological industry standards, the daily meteorological data of 708 weather stations located in the planting regions of double cropping rice in the southern China from 1961 to 2010 and 74 atmospheric circulation characteristics from 1960 to 2010. Methods such as factor puffing, correlation analysis, and stepwise regression were used to establish the prediction models that can discriminate different areas according to risk levels and their spatiotemporal change trends. The average basically consistent accuracy rate of the extended prediction of low temperature damage in highly risk area (I area) by the stepwise regression prediction models was 100% for early rice, 83.3% for Japonica rice and 83.3% for Indica rice. Similarly, as to low risk area with a risk-increasing trend (II area), the prediction accuracy rate was 100% for early rice, 83.3% for Japonica rice and 83.3% for Indica rice; as to low risk area with a risk-decreasing trend (III area), the prediction accuracy rate was 83.3% for early rice, 100% for Japonica rice and 83.3% for Indica rice. The errors of back substitution and prediction of the models to the representative stations of each region were mainly equal to or less than one level. On the whole, the prediction models established in this study had high accuracy. © 2016, Editorial Board of Chinese Journal of Ecology. All Rights Reserved.

Huang Y.,Anhui Meteorological Institute | Chen S.,Advanced Radar Research Center | Chen S.,University of Oklahoma | Cao Q.,Advanced Radar Research Center | And 12 more authors.
Water (Switzerland) | Year: 2014

The latest Version-7 (V7) Tropical Rainfall Measuring Mission (TRMM) Multi-satellite Precipitation Analysis (TMPA) products were released by the NationalAeronautics and Space Administration (NASA) in December of 2012. Their performance on different climatology, locations, and precipitation types is of great interest to the satellite-based precipitation community. This paper presents a study of TMPA precipitation products (3B42RT and 3B42V7) for an extreme precipitation event in Beijing and its adjacent regions (from 00:00 UTC 21 July 2012 to 00:00 UTC 22 July 2012). Measurements from a dense rain gauge network were used as the ground truth to evaluate the latest TMPA products. Results are summarized as follows. Compared to rain gauge measurements, both 3B42RT and 3B42V7 generally captured the rainfall spatial and temporal pattern, having a moderate spatial correlation coefficient (CC, 0.6) and high CC values (0.88) over the broader Hebei, Beijing and Tianjin (HBT) regions, but the rainfall peak is 6 h ahead of gauge observations. Overall, 3B42RT showed higher estimation than 3B42V7 over both HBT and Beijing. At the storm center, both 3B42RT and 3B42V7 presented a relatively large deviation from the temporal variation of rainfall and underestimated the storm by 29.02% and 36.07%, respectively. The current study suggests that the latest TMPA products still have limitations in terms of resolution and accuracy, especially for this type of extreme event within a latitude area on the edge of coverage of TRMM precipitation radar and microwave imager. Therefore, TMPA users should be cautious when 3B42RT and 3B42V7 are used to model, monitor, and forecast both flooding hazards in the Beijing urban area and landslides in the mountainous west and north of Beijing. © 2013 by the authors.

Cao W.,Anhui Meteorological Institute | Cao W.,Anhui Province Atmospheric Science and Satellite Remote Sensing Key Laboratory | Duan C.-F.,Anhui Climate Center | Yao Y.,Anhui Meteorological Institute | And 3 more authors.
Chinese Journal of Applied Ecology | Year: 2014

In this paper, daily reference evapotranspiration (ET0) was computed with the recommended FAO-56 Penman-Monteith equation for Anhui Province using data collected 60 weather stations during 1961 to 2010 and its temporal-spatial variations were characterized. The determining factors in ET0 trends were inquired into through partial derivative quantification analysis for the study region. Results showed that the mean annual ET0 was 878.58 mm • a 1 over the whole region during the study period. ET0 was the highest in summer and the lowest in winter. The mean annual ET0 decreased from the north to the south and from low altitude regions to high altitude regions. Both sunshine duration and wind speed were the dominant factors contributing to the interannual change of ET0, with less contribution from air temperature or relative humidity. The annual ET0 showed a general decline at a rate of -1.61 mm • a-1 owing to a more negative contribution of sunshine duration and wind speed than a positive contribution of air temperature and relative humidity. ET0 increased insignificantly in spring and decreased slightly in both autumn and winter. However, it decreased significantly at a rate of -1.37 mm • a-1 in summer. The main impacting factor was wind speed in spring, autumn and winter, but it was sunshine duration in summer. Great differences in the determining factors of the mean annual ET0 existed from area to area in Anhui Province. The wind speed was the determining factor for 36.7% of the whole stations distributing in the southern part of the area north to the Huaihe River and the area along the Huaihe River, while the sunshine duration was the determining factor for the other regions. ©, 2014, Editorial Board of Chinese Journal of Applied Ecology. All right reserved.

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