نتایج جستجو برای: mean wind speed

تعداد نتایج: 846128  

Journal: :دانش آب و خاک 0
محمد رضا حامی کوچه باغی گروه مهندسی آب دانشگاه تبریز امیر حسین ناظمی استاد- گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز علی اشرف صدرالدینی استاد- گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز رضا دلیر حسن نیا استادیار گروه مهندسی آب دانشکده کشاورزی دانشگاه تبریز

from the mathematical point of view, the fao penman-monteith equation shows a homographic function related to the wind speed. the homographic function has horizontal and vertical asymptotes. in this issue horizontal asymptote is applicable; because the vertical asymptote occurs for negative values of wind speed but the negative sign indicates the direction of the wind speed and only the absolut...

2017
Jiasheng Tian Hang Xue Jian Shi

The neural network algorithm in this paper is applied to the ocean surface wind speed retrievals. Firstly, the Ku band backscattering coefficient (σKu) is considered as the input parameter to retrieve the wind speed and the retrieval precision reaches 1 m/s (root mean square error) for HY2 altimeter. Secondly, by introducing the Ku-band significant wave height (swhku), C-band backscattering coe...

2016
Senthil Kumar Daphne Lopez

Wind energy is rapidly increasing and it is becoming a significant contributor to the electricity grid. Wind speed is an important factor in wind power production and integration. This paper presents a wind speed forecasting using feature selection method and bagging neural network. Feature selection plays an essential role in the machine learning environment and especially in the prediction ta...

Journal: :desert 2014
nozar ghahreman mahsa sameti

evaporation is a fundamental parameter in the hydrological cycle. this study examines the performance of m5model tree and artificial neural network (ann) models in estimating potential evapotranspiration calculated bypenman- monteith and hargreaves- samani equations. daily weather data from two meteorological stations in asemi-arid climate of iran, namely kerman and zahedan, were collected duri...

Abstract. Wind as a resource of renewable energy has obtained an important share of the energy market already. Therefore simulation and prediction of wind speeds is essential for both, for engineers and energy traders. In this paper we analyze the surface wind speed data from three prototypic locations: coastal region (Rotterdam), undulating forest landscape few 100 m above sea level(Kassel), ...

Journal: :Remote Sensing 2016
Lei Zhang Xiao-bin Yin Han-qing Shi Zhenzhan Wang

The realistic and accurate estimation of hurricane intensity is highly desired in many scientific and operational applications. With the advance of passive microwave polarimetry, an alternative opportunity for retrieving wind speed in hurricanes has become available. A wind speed retrieval algorithm for wind speeds above 20 m/s in hurricanes has been developed by using the 6.8 and 10.7 GHz vert...

ژورنال: علوم آب و خاک 2019

The purpose of this study was to model the relationship between the frequency of dust storms and climatic variables in desert areas of Iran. For this purpose, climatic data of temperature (maximum and minimum), rainfall, wind speed (maximum and minimum), and their relationship with the number of days with dust recorded in 25 meteorological stations (statistical period since their inception unti...

Journal: :Remote Sensing 2016
Jianyong Xing Jiancheng Shi Yonghui Lei Xiang-Yu Huang Zhiquan Liu

The first Chinese operational Ku-band scatterometer on board Haiyang-2A (HY-2A), launched in August 2011, is designed for monitoring the global ocean surface wind. This study estimates the quality of the near-real-time (NRT) retrieval wind speed and wind direction from the HY-2A scatterometer for 36 months from 2012 to 2014. We employed three types of sea-surface wind data from oceanic moored b...

2015
H. Wang R. J. Barthelmie S. C. Pryor

Doppler lidars are frequently operated in a mode referred to as arc scans, wherein the lidar beam scans across a sector with a fixed elevation angle and the resulting measurements are used to derive an estimate of the nminute horizontal mean wind velocity (speed and direction). Previous studies have shown that the uncertainty in the measured wind speed originates from turbulent wind fluctuation...

2010
Xiaoqian Jiang Bing Dong Le Xie Latanya Sweeney

We study the problem of short term wind speed prediction, which is a critical factor for effective wind power generation. This is a challenging task due to the complex and stochastic behavior of the wind environment. Observing various periods in the wind speed time series present different patterns, we suggest a nonlinear adaptive framework to model various hidden dynamic processes. The model i...

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