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您的检索式：作者名="Mohamed Freeshah"
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| 1 | TDS-1 GNSS reflectometry wind geophysical model function response to GPS block types显示文摘This paper presents the TDS-1 GNSS reflectometry wind Geophysical Model Function(GMF)response to GPS block types.The observables were extracted from Delay Doppler Maps(DDMs)after taking the receiver antenna gains effects and GNSS-R geometry effects into account.Since the DDM is affected by GPS EffectiveIsotropic Radiated Power(EIRP),we first investigate the sensitivity of observables to the GPS block.Additionally,the observables at high SNRs are more sensitive to wind speed,but the spatial coverage at high signal to noise ratios(SNRs)is lower,while DDMs at low SNRs have the opposite characteristics.To balance the accuracy and spatial coverage,the DDM datasets are divided into two parts:high SNR(>0 dB)and low SNR(>−10 dB and≤0 dB)to develop wind GMF.Then,the influences of GPS block on wind speed retrieval both at high and low SNR is analyzed.Results show that the block types have impacts on wind GMF and the use of a prior GPS block can contribute to a better wind speed retrieval both at high and low SNR.Compared with ASCAT,the Root Mean Square Error(RMSE)value of wind speed retrieval at high and low SNR are 2.19 m/s and 3.13 m/s,respectively,when all TDS data are processed without distinguishing GPS block types.However,if the TDS data are separately processed and used to develop wind GMF through different blocks,both the accuracy and correlation coefficient can be improved to some extent.Finally,the influence of significant height of the swell(Hs)on SNR observables is analyzed,and it is demonstrated that there is no obvious linear or nonlinear relationship between them. | Fade Chen Xiaohong Zhang Fei Guo Jiazhu Zheng Yang Nan Mohamed Freeshah | 2022 | Geo-Spatial Information Science2022，25，2： | 1 |
| 2 | Soil erosion assessment by RUSLE model using remote sensing and GIS in an arid zone显示文摘In this research,we used the Revised Universal Soil Loss Equation(RUSLE)and Geographical Information System(GIS)to predict the annual rate of soil loss in the District Chakwal of Pakistan.The parameters of the RUSLE model were estimated using remote sensing data,and the erosion probability zones were determined using GIs.The estimated length slope(LS),crop management(C),rainfall erosivity(R),soil erodibility(K),and support practice(P)range from 0-68,227,0-66.61%,0-0.58,495.99-648.68 MJ/mm.t.ha^(-1).year^(-1),0.15-0.25 MJ/mm.t.ha^(-1).year^(-1),and 1 respectively.The results indicate that the estimated total annual potential soi loss of approximately 4,67,064.25 t.ha^(-1).year^(-1) is comparable with the measured'sediment ioss of 11,631 t.ha^(-1).year^(-1) during the water year 2020.The predicted soil erosion rate due to an increase in agricultural area is approximately 164,249.31 t.ha^(-1).year^(-1).In this study,we also used,Landsat imagery to rapidly achieve actual land use classification.Meanwhile,38.i3%of the region was threatened by very high soil erosion,where the quantity of soil erosion ranged from 365487.35 t.ha^(-1).year^(-1),Integrating GIS and remote sensing with the RUSLE model helped researchers achieve their final objectives.Land-use planners and decision-makers use the result's spatial distribution of soil erosion in District Chakwal for conservation and management planning. | Pingheng Li Aqil Tariq Qingting Li Bushra Ghaffar Muhammad Farhan Ahsan Jamil Walid Soufan Ayman El Sabagh Mohamed Freeshah | 2023 | International Journal of Digital Earth2023，16，1： | 0 |
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