Nomhon, China
Nomhon, China

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Zheng C.,Dalian University of Technology | Zheng C.,Meteorological Unit | Shao L.,Dalian University of Technology | Lin G.,Dalian University of Technology | And 2 more authors.
Harbin Gongcheng Daxue Xuebao/Journal of Harbin Engineering University | Year: 2014

There has been little research done on the ditching probability in a large area at present, which is insufficient for providing proper reference for route planning of sea-skimming. In this study, the typhoon wave caused by "Muifa" was simulated using the simulating waves nearshore (SWAN) wave model with the cross-calibrated, multi-platform (CCMP) wind field as the driving field, and the analysis of the ditching probability in a large area was realized. Results show that the SWAN wave model depicts the typhoon wave field very well. The simulated wave data has high precision, and the simulated significant wave height (SWH) is slightly bigger than the observed SWH. During typhoon "Muifa", the large value area of the SWH was mainly distributed in the dangerous semicircle, especially the fourth quadrant. The ditching probability field of the China Sea was affected by typhoon "Muifa" significantly. When the flying height is 5 m above the sea surface, the ditching probability in most of the China Sea is above 60%, and can even extend above 85% in the dangerous semicircle. When the flying height is 10 m, the ditching probability is about 30% lower than when the flying height is 5 m.


Kidron G.J.,Hebrew University of Jerusalem | Kronenfeld R.,Meteorological Unit
Ecohydrology | Year: 2015

Global warming may affect the moisture content of soil, subsequently affecting plant productivity. This is all the more so in deserts where water is the major limiting factor. In an attempt to evaluate the possible effect of temperature rise on pan and soil evaporation, the evaporation rates of water from variable-size pans and of plots of variable degree of shading (all with different water/soil temperatures) were compared. A close link between the water temperature of the pan (resulting from the different diameter-size pans) and class A pan evaporation was found. The data showed that an increase of 1°C in the maximum temperatures implied an increase of 0.08mm/day, i.e. ~8.3% in the evaporation rate of the pan. Similarly, an increase in the subsurface temperatures (at 5cm depth) substantially decreased the available water content at the 0- to 10-cm soil, with the evaporation rate increasing by 0.07mm/day (~6.6%) for each 1°C increase in soil temperature. The findings suggest an increase of ~10% in the evaporation rate of the soil surface for each 1°C increase in soil temperature. The advantage in estimating the possible effect of temperature rise upon soil evaporation via shaded plots in comparison with the classical approach of soil heating is discussed, as well as the possible effect of temperature rise on biocrusts, seedling germination and plant productivity. © 2015 John Wiley & Sons, Ltd.


Zheng C.W.,Nanjing University of Science and Technology | Zheng C.W.,CAS Institute of Atmospheric Physics | Zheng C.W.,Meteorological Unit | Zhou L.,Nanjing University of Science and Technology | And 3 more authors.
Journal of Renewable and Sustainable Energy | Year: 2014

This study presents the characteristics of the China Sea wave energy resource and wave climate for the period August 1999 to July 2009, using a 10-yr hindcast wave data obtained from WAVEWATCH-III (WW3) numerical wave model forced with QuikSCAT/NCEP (QN) wind data. Results show that: (1) The China Sea wave field has significant seasonal differences, especially the South China Sea which is obviously affected by the monsoon. In JJA (June, July, August), the dominant wave direction is south to southwest. In DJF (December, January, February), the dominant wave direction is north to northeast. The Luzon Strait is the relative large center of significant wave height in DJF (2.4-2.8m), SON (September, October, November) (2.0-2.4m), and MAM (March, April, May) (1.0-1.4m), while the southeast area of the Indo-China Peninsula is the large center in JJA (1.2-1.6m). (2) The rough sea occurrence in the China Sea is relative low, of below 14% in each season. The relative high occurrence happened in DJF, followed by the SON, lowest in MAM. (3) The extreme wave height with return period of 20 yr in the Bohai Sea, Yellow Sea, low latitude of the South China Sea is below 8m. The large areas mainly distribute in the middle latitude. The distribution of extreme wave height with return period of 30 yr is similar and about 2m larger than that with return period of 20 yr. (4) We find the China Sea wave power increases gradually from MAM to DJF. The Luzon Strait is the relative large region of wave power in DJF (30-40kW/m), SON (21-27kW/m), and MAM (6-10kW/m), while the southeast area of the Indo-China Peninsula is the large center in JJA (6-11kW/m). (5) The stability of the China Sea wave power exhibits obvious regional and seasonal differences. The wave power is the most stable in DJF. The wave power in the north area of the South China and East Sea is apparently more stable than that in other sea areas, in the offshore is more stable than that in the near shore. (6) Judging from the value and stability of wave power, we find that the relative rich-energy region locates in the Luzon Strait and adjacent waters in DJF, SON, and MAM, while in the southeast area of the Indo-China Peninsula in JJA. © 2014 AIP Publishing LLC.


Zheng C.,PLA University of Science and Technology | Zheng C.,Meteorological Unit | Zhou L.,PLA University of Science and Technology | Huang C.,PLA University of Science and Technology | And 2 more authors.
Acta Oceanologica Sinica | Year: 2013

Utilizing the 45 a European Centre for Medium-Range Weather Forecasts (ECMWF) reanalysis wave data (ERA-40), the long-term trend of the sea surface wind speed and (wind wave, swell, mixed wave) wave height in the global ocean at grid point 1.5° ×1.5° during the last 44 a is analyzed. It is discovered that a majority of global ocean swell wave height exhibits a significant linear increasing trend (2-8 cm/decade), the distribution of annual linear trend of the significant wave height (SWH) has good consistency with that of the swell wave height. The sea surface wind speed shows an annually linear increasing trend mainly concentrated in the most waters of Southern Hemisphere westerlies, high latitude of the North Pacific, Indian Ocean north of 30° S, the waters near the western equatorial Pacific and low latitudes of the Atlantic waters, and the annually linear decreasing mainly in central and eastern equator of the Pacific, Juan. Fernandez Archipelago, the waters near South Georgia Island in the Atlantic waters. The linear variational distribution characteristic of the wind wave height is similar to that of the sea surface wind speed. Another find is that the swell is dominant in themixed wave, the swell index in the central ocean is generally greater than that in the offshore, and the swell index in the eastern ocean coast is greater than that in thewestern ocean inshore, and in year-round hemisphere westerlies the swell index is relatively low. © 2013 The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg.


Zheng C.,Dalian University of Technology | Zheng C.,Nanjing University of Science and Technology | Zheng C.,Meteorological Unit | Shao L.,Dalian University of Technology | And 6 more authors.
Acta Oceanologica Sinica | Year: 2014

Against the background of the current world facing an energy crisis, and human beings puzzled by the problems of environment and resources, developing clean energy sources becomes the inevitable choice to deal with a climate change and an energy shortage. A global ocean wave energy resource was reanalyzed by using ERA-40 wave reanalysis data 1957-2002 from European Centre for Medium-Range Weather Forecasts (ECMWF). An effective significant wave height is defined in the development of wave energy resources (short as effective SWH), and the total potential of wave energy is exploratively calculated. Synthetically considering a wave energy density, a wave energy level probability, the frequency of the effective SWH, the stability and long-termtrend of wave energy density, a swell index and a wave energy storage, global ocean wave energy resources were reanalyzed and regionalized, providing reference to the development of wave energy resources such as wave power plant location, seawater desalination, heating, pumping. © The Chinese Society of Oceanography and Springer-Verlag Berlin Heidelberg 2014.

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