Hainan, China
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Zhu J.,Hainan Climate Center | Zhu J.,Key Laboratory of Meteorological Disaster Prevention and Reduction of South China Sea | Zhang J.,Hainan Climate Center | Zhang J.,Key Laboratory of Meteorological Disaster Prevention and Reduction of South China Sea | And 5 more authors.
Journal of Natural Disasters | Year: 2014

Rainstorm is one of the major weather disasters of the new satellite launch center in Wenchang City of Hainan Province, which will cause unpredictable disasters in test task of the site. Using the daily precipitation data of Wenchang meteorological station and global reanalysis gridded data of NCEP/NCAR from 1970 to 2010 and based on seven weather systems (cold procsee from east, cold procsee from west, subtropical high, warm ridge of high pressure, South China Sea trough, southwest trough, Vietnam trough) , this paper statistically analyzed the climatic characteristics and the conceptual cause model of the non-typhoon rainstorm weather process in Wenchang region of Hainan Province during recent 41 years under influence of each kind of weather system. Results show that, the annual frequency of the non-typhoon rainstorm in the launch site region has a tendency of slow rise, with the number of the annual rainstorms slowly increases. The distribution of monthly occurrence number shows " quasi-bimodal" characteristic. The main peak is in the September and October. The second peak is in May and June. The non-typhoon rainstorm occurs mainly from April to October. In addition, geopotential height, wind and moisture distribution can well characterize the non-typhoon rainstorm circulation features.

Zhu R.,National Climate Center | Badger M.,Technical University of Denmark | Hasager C.B.,Technical University of Denmark | Xing X.,Hainan Climate Center
Remote Sensing | Year: 2015

Using accurate inputs of wind speed is crucial in wind resource assessment, as predicted power is proportional to the wind speed cubed. This study outlines a methodology for combining multiple ocean satellite winds and winds from WRF simulations in order to acquire the accurate reconstructed offshore winds which can be used for offshore wind resource assessment. First, wind speeds retrieved from Synthetic Aperture Radar (SAR) and Scatterometer ASCAT images were validated against in situ measurements from seven coastal meteorological stations in South China Sea (SCS). The wind roses from the Navy Operational Global Atmospheric Prediction System (NOGAPS) and ASCAT agree well with these observations from the corresponding in situ measurements. The statistical results comparing in situ wind speed and SAR-based (ASCAT-based) wind speed for the whole co-located samples show a standard deviation (SD) of 2.09 m/s (1.83 m/s) and correlation coefficient of R 0.75 (0.80). When the offshore winds (i.e., winds directed from land to sea) are excluded, the comparison results for wind speeds show an improvement of SD and R, indicating that the satellite data are more credible over the open ocean. Meanwhile, the validation of satellite winds against the same co-located mast observations shows a satisfactory level of accuracy which was similar for SAR and ASCAT winds. These satellite winds are then assimilated into the Weather Research and Forecasting (WRF) Model by WRF Data Assimilation (WRFDA) system. Finally, the wind resource statistics at 100 m height based on the reconstructed winds have been achieved over the study area, which fully combines the offshore wind information from multiple satellite data and numerical model. The findings presented here may be useful in future wind resource assessment based on satellite data. © 2014 by the authors.

Xing X.-H.,Lanzhou University | Xing X.-H.,Hainan Climate Center | Zhu R.,National Climate Center | Zhai P.-M.,China Meteorological Administration | Yu W.,Environment Canada
Journal of Tropical Meteorology | Year: 2010

With high resolution (1 km), the distribution of wind energy resources in Hainan province and over its offshore waters is numerically simulated by using the Wind Energy Simulation Toolkit (WEST) model developed by Meteorological Research Branch of Environment Canada. Compared with observations from eight coastal anemometric towers and 18 existing stations in the province, the simulations show good reproduction of the real distribution of wind resources in Hainan and over its offshore waters, with the relative error of annual mean wind speed being no more than 9% at the 70-m level. Moreover, based on the simulated results of WEST grids that are closest to where the eight wind towers are located, the annual mean wind speeds are further estimated by using the Danish software WasP (Wind Atlas Analysis and Application Program). The estimated results are then compared with the observations from the towers. It shows that the relative error is also less than 9%. Therefore, WEST and WEST+WAsP will be useful tools for the assessment of wind energy resources in high resolution and selection of wind farm sites in Hainan province and over its offshore waters.

Cai D.,Research Institute of Hainan Meteorological Bureau | Zhang J.,Hainan Climate Center | Zou H.,Research Institute of Hainan Meteorological Bureau | Liu S.,Hainan Climate Center
Journal of Natural Disasters | Year: 2013

Cold damage seriously affects and restricts the development of banana planting industry in Hainan. It is of great importance to study the insurance of cold-damaged banana to reduce agricultural losses and economic growth of Hainan. With the data of yields of banana during 1990-2010 and data of weather of 18 cities/countries in Hainan Island from 1961 to 2010, historical sequences of banana yield reduction caused by cold damage were calculated, and based on the extreme value theory, distribution models of yield risk were constructed, and the pure premium rates of the study areas were collated and stipulated. The results show that 1960s to 1980s is a period of frequent cold damages in Hainan Island. However, the disasters declined after the 1990s. The middle and north of Hainan Island are areas with high pure premium rates, including Baisha, Qiongzhong, Wuzhishan and Chengmai, while the south and east areas are the opposite. The spatial distribution of the rates is generally consistent with the distribution of weather risk of cold damage. It is possible to approximate and adopt different deductible rates in different regions. When the rates are collated and stipulated, the trends of cold damage risk change should be taken into account.

Liu S.,Hainan Climate Center | Liu S.,Research Institute of Hainan Meteorological Bureau | Zhang J.,Hainan Climate Center | Cai D.,Research Institute of Hainan Meteorological Bureau | Zhang M.,Hainan Climate Center
Journal of Natural Disasters | Year: 2014

Disaster assessment models usually are established with a large number of historical statistics. However, the data are often incomplete or statistics disaster measure inconsistent, which will bring some inconvenience in the establishment of disaster model. In order to rapidly assess typhoon's impact on rubber plant, typical case typhoon "David" was analyzed in the enlightenment of the reverse engineering design thinking. The assessment model factors were chosen from disaster pregnant environment, disaster-formative factors, and disaster-affected bodies. The evaluation model was established by analyzing the extent of natural rubber damage and related factors, and actual example tests were carried out on the model. Results show that, the model reflects the spatial distribution of rubber damage loss in some degree. The model would be the foundation for establishing more accurate assessment model.

Xu X.-C.,Hainan Institute of Meteorological Science | Xin J.-W.,Hainan Institute of Meteorological Science | Liang G.-F.,Yangjiang Meteorological Bureau | Xing X.-H.,Hainan Climate Center | And 2 more authors.
Journal of Tropical Meteorology | Year: 2010

The spatial variation and diurnal fluctuation of sea surface wind over the Qiongzhou Strait were described using verified datasets from automatic weather stations on board a ferry, buoys, and on the coast. Results are as follows: (1) On average, sea surface wind speed is 3-4 m/s larger over the Qiongzhou Strait than in the coastal area. Sea surface wind speeds of 8.0 m/s or above (on Beaufort scale five) in the coastal area are associated with speeds 5-6 m/s greater over the surface of the Qiongzhou Strait. (2) Gust coefficients for the Qiongzhou Strait decrease along with increasing wind speeds. When coastal wind speed is less than scale five, the average gust coefficient over the sea surface is between 1.4 and 1.5; when wind speed is equal to scale five or above, the average gust coefficient is about 1.35. (3) In autumn and winter, the diurnal differences of average wind speed and wind consistency over the strait are less than those in the coastal area; when wind speed is 10.8 m/s (scale six) or above, the diurnal difference of average wind speed decreases while wind consistency increases for both the strait and the coast.

Liu S.,Hainan Climate Center | Liu S.,Key Laboratory of Meteorological Disaster Prevention | Zhang J.,Hainan Climate Center | Zhang J.,Key Laboratory of Meteorological Disaster Prevention | And 3 more authors.
Journal of Natural Disasters | Year: 2014

Data Envelopment Analysis (DEA) model is an input-output efficiency evaluation model. Because its operation does not involve any weight hypothesis, many subjective factors are avoided, and so it has been widely used in efficiency evaluation. Because the formation of mountain flood disaster is influenced by many factors, and each factor contains many forms of expressions, to avoid and reduce the subjectivity of evaluation and promote the objectivity of evaluation, the DEA model is adopted to rank the hazard of mountain flood disasters in Hainan Island with topographic factor, water factor, rainstorm day index, landslide and debris flow density and comprehensive disaster degree as assessment indies. By contrast with the history mountain flood disaster, it is shown that, application of DEA method to the mountain flood disaster assessment is feasible.

Wu H.,Hainan Climate Center | Wu H.,Lanzhou University | Zhai P.,Chinese Academy of Meteorological Sciences | Chen Y.,Chinese Academy of Meteorological Sciences
Journal of Meteorological Research | Year: 2016

Based on observational precipitation at 63 stations in South China and NCEP–NCAR reanalysis data during 1951–2010, a cluster analysis is performed to classify large-scale circulation patterns responsible for persistent precipitation extremes (PPEs) that are independent of the influence of tropical cyclones (TCs). Conceptual schematics depicting configurations among planetary-scale systems at different levels are established for each type. The PPEs free from TCs account for 38.6% of total events, and they tend to occur during April–August and October, with the highest frequency observed in June. Corresponding circulation patterns during June–August can be mainly categorized into two types, i.e., summer-I type and summer-II type. In summer-I type, the South Asian high takes the form of a zonal-belt type. The axis of upstream westerly jets is northwest-oriented. At the middle level, the westerly jets at midlatitudes extend zonally. Along the southern edge of the westerly jet, synoptic eddies steer cold air to penetrate southward; the Bay of Bengal (BOB) trough is located to the north; a shallow trough resides over coastal areas of western South China; and an intensified western Pacific subtropical high (WPSH) extends westward. The anomalous moisture is mainly contributed by horizontal advection via southwesterlies around 20 °N and southeasterlies from the southern flange of the WPSH. Moisture convergence maximizes in coastal regions of eastern South China, which is the very place recording extreme precipitation. In summer-II type, the South Asian high behaves as a western-center type. The BOB trough is much deeper, accompanied by a cyclone to its north; and a lower-level trough appears in northwestern parts of South China. Different to summer-I type, moisture transport via southwesterlies is mostly responsible for the anomalous moisture in this type. The moisture convergence zones cover Guangdong, Guangxi, and Hainan, matching well with the areas of flooding. It is these set combinations among different systems at different levels that trigger PPEs in South China. © 2016, The Chinese Meteorological Society and Springer-Verlag Berlin Heidelberg.

Liu S.,Hainan Institute of Meteorological Science | Zhang J.,Hainan Climate Center | Cai D.,Hainan Institute of Meteorological Science | Zhang M.,Hainan Climate Center | And 2 more authors.
Journal of Natural Disasters | Year: 2015

For the fluctuation of rubber plant yield are related closely to meteorological conditions, so risk regionalization of the rubber plant yield loss should fully consider the impact of meteorological disasters. Rubber yield reduction sequences were extracted from the actual output data of rubber plant in 18 counties of Hainan Island from 1988 to 2010. The average rubber yield reduction rate, variation coefficient of yield reduction rate, risk index of yield reduction rate and comprehensive regional risk coefficient of meteorological disaster were chosen as the evaluation factors to conduct rubber yield loss risk regionalization. The results show that the high risk regions of rubber plant losses are mainly located in Wenchang, Dongfang, Changjiang, Sanya, Lingshui; middle risk areas are mainly located in Dingan, Qionghai, Qiongzhong, Wanning, Ledong etc.; low risk areas are located in Haikou, Chengmai, Danzhou, Tunchang, Baisha, Wuzhishan, Baoting and so on.

Wu H.,Hainan Climate Center | Wu H.,Chinese Academy of Meteorological Sciences | Zhai P.,Chinese Academy of Meteorological Sciences
Acta Meteorologica Sinica | Year: 2013

The characteristics and possible causes of changes in persistent precipitation (PP) and non-persistent precipitation (NPP) over South China during flood season are investigated using daily precipitation data from 63 stations in South China and NCEP/NCAR reanalysis data from 1961 to 2010. This investigation is performed using the Kendall's tau linear trend analysis, correlation analysis, abrupt climate change analysis, wavelet analysis, and composite analysis techniques. The results indicate that PP dominates total precipitation over South China throughout the year. The amounts of PP and NPP during flood season vary primarily on a 2-5-yr oscillation. This oscillation is more prominent during the early flood season (EFS; April-June). NPP has increased significantly over the past 50 years while PP has increased slightly during the whole flood season. These trends are mainly due to a significant increase in NPP during the EFS and a weak increase in PP during the late flood season (LFS; July-September). The contribution of EFS NPP to total flood season precipitation has increased significantly while the contribution of EFS PP has declined. The relative contributions of both types of precipitation during LFS have not changed significantly. The increase in EFS NPP over South China is likely related to the combined effects of a stronger supply of cold air from the north and a weaker supply of warm, moist air from the south. The increase in NPP amount may also be partially attributable to a reduction in the stability of the atmosphere over South China. © 2013 The Chinese Meteorological Society and Springer-Verlag Berlin Heidelberg.

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