Dynamic b_p in the L Band and Its Role in Improving the Accuracy of Soil Moisture Retrieval
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摘要
The parameter b_p in the tuo-omega(τ–ω)model is important for retrieving soil moisture data from passive microwave brightness temperatures.Theoretically,b_p depends on the observation mode(polarization,frequency,and incidence angle)and vegetation properties and varies with vegetation growth.For simplicity,previous studies have taken b_p to be a constant.However,to reduce the uncertainty of soil moisture retrieval further,the present study is of the dynamics of b_p based on the SMAPVEX12 experimental dataset by combining a genetic algorithm and the L-MEB microwave radiative transfer model of vegetated soil.The results show the following.First,b_p decreases nonlinearly with vegetation water content(VWC),decreasing critically when VWC becomes less than 2 kg/m~2.Second,there is a power law between b_p and VWC for both horizontal and vertical polarizations(R~2=0.919 and 0.872,respectively).Third,the effectiveness of this relationship is verified by comparing its soil-moisture inversion accuracy with the previous constant-b_p method based on the HiWATER dataset.Doing so reveals that the dynamic b_p method reduces the root-mean-square error of the retrieved soil moisture by approximately 0.06 cm~3/cm~3,and similar improvement is obtained for the calibrated SMAPVEX12 dataset.Our results indicate that the dynamic b_p method is reasonable for different vegetation growth stages and could improve the accuracy of soil moisture retrieval.
The parameter b_p in the tuo-omega(τ–ω)model is important for retrieving soil moisture data from passive microwave brightness temperatures.Theoretically,b_p depends on the observation mode(polarization,frequency,and incidence angle)and vegetation properties and varies with vegetation growth.For simplicity,previous studies have taken b_p to be a constant.However,to reduce the uncertainty of soil moisture retrieval further,the present study is of the dynamics of b_p based on the SMAPVEX12 experimental dataset by combining a genetic algorithm and the L-MEB microwave radiative transfer model of vegetated soil.The results show the following.First,b_p decreases nonlinearly with vegetation water content(VWC),decreasing critically when VWC becomes less than 2 kg/m~2.Second,there is a power law between b_p and VWC for both horizontal and vertical polarizations(R~2=0.919 and 0.872,respectively).Third,the effectiveness of this relationship is verified by comparing its soil-moisture inversion accuracy with the previous constant-b_p method based on the HiWATER dataset.Doing so reveals that the dynamic b_p method reduces the root-mean-square error of the retrieved soil moisture by approximately 0.06 cm~3/cm~3,and similar improvement is obtained for the calibrated SMAPVEX12 dataset.Our results indicate that the dynamic b_p method is reasonable for different vegetation growth stages and could improve the accuracy of soil moisture retrieval.
The parameter b_p in the tuo-omega(τ–ω)model is important for retrieving soil moisture data from passive microwave brightness temperatures.Theoretically,b_p depends on the observation mode(polarization,frequency,and incidence angle)and vegetation properties and varies with vegetation growth.For simplicity,previous studies have taken b_p to be a constant.However,to reduce the uncertainty of soil moisture retrieval further,the present study is of the dynamics of b_p based on the SMAPVEX12 experimental dataset by combining a genetic algorithm and the L-MEB microwave radiative transfer model of vegetated soil.The results show the following.First,b_p decreases nonlinearly with vegetation water content(VWC),decreasing critically when VWC becomes less than 2 kg/m~2.Second,there is a power law between b_p and VWC for both horizontal and vertical polarizations(R~2=0.919 and 0.872,respectively).Third,the effectiveness of this relationship is verified by comparing its soil-moisture inversion accuracy with the previous constant-b_p method based on the HiWATER dataset.Doing so reveals that the dynamic b_p method reduces the root-mean-square error of the retrieved soil moisture by approximately 0.06 cm~3/cm~3,and similar improvement is obtained for the calibrated SMAPVEX12 dataset.Our results indicate that the dynamic b_p method is reasonable for different vegetation growth stages and could improve the accuracy of soil moisture retrieval.
引文
Burke E J,Wigneron J P,Gurney R J,1999.Research Note:the comparison of two models that determine the effects of a vegetation canopy on passive microwave emission.Hydrology and Earth System Sciences,3(3):439-444.doi:10.5194/hess-3-439-1999
Choudhury B J,Schmugge T J,Mo T,1982.A parameterization of effective soil temperature for microwave emission.Journal of Geophysical Research:Oceans,87(C2):1301-1304.doi:10.1029/JC087iC02p01301
Entekhabi D,Yueh S,O’Neill P E et al.,2014.SMAP Handbook:Soil Moisture Active Passive,Mapping Soil Moisture and Freeze/Thaw from Space.Pasadena,CA:JPL Publication.
Escorihuela M J,Kerr Y H,de Rosnay P et al.,2007.A simple model of the bare soil microwave emission at L-band.IEEE Transactions on Geoscience and Remote Sensing,45(7):1978-1987.doi:10.1109/TGRS.2007.894935
Fan L,Xiao Q,Wen J G et al.,2015.Mapping high-resolution soil moisture over heterogeneous cropland using multiresource remote sensing and ground observations.Remote Sensing,7(10):13273-13297.doi:10.3390/rs71013273
Goldberg D E,1989.Genetic Algorithms in Search,Optimization,and Machine Learning.Reading,Mass.:Addison-Wesley Professional.
Holmes T R H,De Rosnay P,De Jeu R et al.,2006.A new parameterization of the effective temperature for L band radiometry.Geophysical Research Letters,33(7):L07405.doi:10.1029/2006GL025724
Jackson T J,Schmugge T J,Wang J R,1982.Passive microwave sensing of soil moisture under vegetation canopies.Water Resources Research,18(4):1137-1142.doi:10.1029/WR018i004p01137
Jackson T J,Schmugge T J,1991.Vegetation effects on the microwave emission of soils.Remote Sensing of Environment,36(3):203-212.doi:10.1016/0034-4257(91)90057-D
Jackson T J,O’Neill P E,1990.Attenuation of soil microwave emission by corn and soybeans at 1.4 and 5 GHz.IEEE Transactions on Geoscience and Remote Sensing,28(5):978-980.doi:10.1109/36.58989
Kerr Y H,Waldteufel P,Richaume P et al.,2012.The SMOS soil moisture retrieval algorithm.IEEE Transactions on Geoscience and Remote Sensing,50(5):1384-1403.doi:10.1109/TGRS.2012.2184548
Kurum M,2013.Quantifying scattering albedo in microwave emission of vegetated terrain.Remote Sensing of Environment,129:66-74.doi:10.1016/j.rse.2012.10.021
Le Vine D M,Karam M A,1996.Dependence of attenuation in a vegetation canopy on frequency and plant water content.IEEE Transactions on Geoscience and Remote Sensing,34(5):1090-1096.doi:10.1109/36.536525.
Li Dazhi,Jin Rui,Che Tao et al.,2014.Soil moisture retrieval from airborne PLMR and MODIS products in the Zhangye oasis of middle stream of the Heihe River Basin,China.Advances in Earth Science,29(2):295-305.(in Chinese)
Li X,Cheng G D,Liu S M et al.,2013.Heihe watershed allied telemetry experimental research(HiWATER):scientific objectives and experimental design.Bulletin of the American Meteorological Society,94(8):1145-1160.doi:10.1175/BAMS-D-12-00154.1
Loew A,2008.Impact of surface heterogeneity on surface soil moisture retrievals from passive microwave data at the regional scale:the Upper Danube case.Remote Sensing of Environment,112(1):231-248.doi:10.1016/j.rse.2007.04.009
Ma M G,Chen Y Y,Wang X F et al.,2013.Hi WATER:Dataset of Soil Parameters in the Middle Reaches of the Heihe River Basin.Lanzhou,China:Heihe Plan Science Data Center.doi:10.3972/hiwater.147.2013.db
Mironov V L,Kosolapova L G,Fomin S V,2009.Physically and mineralogically based spectroscopic dielectric model for moist soils.IEEE Transactions on Geoscience and Remote Sensing,47(7):2059-2070.doi:10.1109/TGRS.2008.2011631
Njoku E G,Jackson T J,Lakshmi V et al.,2003.Soil moisture retrieval from AMSR-E.IEEE Transactions on Geoscience and Remote Sensing,41(2):215-229.doi:10.1109/TGRS.2002.808243
Pampaloni P,Paloscia S,1986.Microwave emission and plant water content:a comparison between field measurements and theory.IEEE Transactions on Geoscience and Remote Sensing,GE-24(6):900-905.doi:10.1109/TGRS.1986.289705
Panciera R,Walker J P,Kalma J D et al.,2009.Evaluation of the SMOS L-MEB passive microwave soil moisture retrieval algorithm.Remote Sensing of Environment,113(2):435-444.doi:10.1016/j.rse.2008.10.010
PardéM,Wigneron J P,Chanzy A et al.,2003.Retrieving surface soil moisture over a wheat field:comparison of different methods.Remote Sensing of Environment,87(2-3):334-344.doi:10.1016/j.rse.2003.08.002
Pellarin T,Wigneron J P,Calvet J C et al.,2003.Two-year global simulation of l-band brightness temperatures over land.IEEE Transactions on Geoscience and Remote Sensing,41(9):2135-2139.doi:10.1109/TGRS.2003.815417
Saleh K,Wigneron J P,Waldteufel P et al.,2007.Estimates of surface soil moisture under grass covers using L-band radiometry.Remote Sensing of Environment,109(1):42-53.doi:10.1016/j.rse.2006.12.002
SMAP,2012a.SMAP Validation Experiment 2012(SMAPVEX12)Experimental Plan.https://smapvex12.espaceweb.usherbrooke.ca/SMAPVEX12_Experiment_Plan.pdf.Updated 22 May 2012.
SMAP,2012b.SMAP Validation Experiment 2012(SMAPVEX12)Database Report.https://smapvex12.espaceweb.usherbrooke.ca/SMAPVEX12_Database_Report_final.pdf.Updated 18 December 2012.
Ulaby F T,Moore R K,Fung A K,1986.Microwave Remote Sensing vol.III,From Theory to Applications.London,UK:Artech House.
Ulaby F T,Tavakoli A,Thomas B A,1987.Microwave propagation constant for a vegetation canopy with vertical stalks.IEEE Transactions on Geoscience and Remote Sensing,GE-25(6):714-725.doi:10.1109/TGRS.1987.289741
Van De Griend A A,Owe M,De Ruiter J et al.,1996.Measurement and behavior of dual-polarization vegetation optical depth and single scattering albedo at 1.4-and 5-GHz microwave frequencies.IEEE Transactions on Geoscience and Remote Sensing,34(4):957-965.doi:10.1109/36.508412
Van de Griend A A,Wigneron J P,Waldteufel P,2003.Consequences of surface heterogeneity for parameter retrieval from1.4-GHz multiangle SMOS observations.IEEE Transactions on Geoscience and Remote Sensing,41(4):803-811.doi:10.1109/TGRS.2003.811083
Van De Griend A A,Wigneron J P,2004.The b-factor as a function of frequency and canopy type at H-polarization.IEEE Transactions on Geoscience and Remote Sensing,42(4):786-794.doi:10.1109/TGRS.2003.821889
Wang J R,Choudhury B J,1981.Remote sensing of soil moisture content,over bare field at 1.4 GHz frequency.Journal of Geophysical Research,86(C6):5277-5282.doi:10.1029/JC086i C06p05277
Wigneron J P,Chanzy A,Calvet J C et al.,1995a.A simple algorithm to retrieve soil moisture and vegetation biomass using passive microwave measurements over crop fields.Remote Sensing of Environment,51(3):331-341.doi:10.1016/0034-4257(94)00081-W
Wigneron J P,Calvet J C,Chanzy A et al.,1995b.A composite discrete-continuous approach to model the microwave emission of vegetation.IEEE Transactions on Geoscience and Remote Sensing,33(1):201-210.doi:10.1109/36.368208
Wigneron J P,Calvet J C,Kerr Y,1996.Monitoring water interception by crop fields from passive microwave observations.Agricultural and Forest Meteorology,80(2-4):122-194.doi:10.1016/0168-1923(95)02296-1
Wigneron J P,Laguerre L,Kerr Y H,2001.A simple parameterization of the L-band microwave emission from rough agricultural soils.IEEE Transactions on Geoscience and Remote Sensing,39(8):1697-1707.doi:10.1109/36.942548
Wigneron J P,Calvet J C,De Rosnay P et al.,2004a.Soil moisture retrievals from biangular L-band passive microwave observations.IEEE Geoscience and Remote Sensing Letters,1(4):277-281.doi:10.1109/LGRS.2004.834594
Wigneron J P,PardéM,Waldteufel P et al.,2004b.Characterizing the dependence of vegetation model parameters on crop structure,incidence angle,and polarization at L-band.IEEE Transactions on Geoscience and Remote Sensing,42(2):416-425.doi:10.1109/TGRS.2003.817976
Wigneron J P,Andersen S,Boutin J et al.,2006.Surface emission.In:M?tzler C(ed).Thermal Microwave Radiation:Applications for Remote Sensing.London,UK:The Institution of Engineering and Technology.
Wigneron J P,Kerr Y,Waldteufel P et al.,2007.L-band microwave emission of the biosphere(L-MEB)model:description and calibration against experimental data sets over crop fields.Remote Sensing of Environment,107(4):639-655.doi:10.1016/j.rse.2006.10.014
Yan S,Jiang L M,Chai L N et al.,2015.Calibration of the L-MEB model for croplands in HiWATER using PLMR observation.Remote Sensing,7(8):10878-10897.doi:10.3390/rs70810878
Choudhury B J,Schmugge T J,Mo T,1982.A parameterization of effective soil temperature for microwave emission.Journal of Geophysical Research:Oceans,87(C2):1301-1304.doi:10.1029/JC087iC02p01301
Entekhabi D,Yueh S,O’Neill P E et al.,2014.SMAP Handbook:Soil Moisture Active Passive,Mapping Soil Moisture and Freeze/Thaw from Space.Pasadena,CA:JPL Publication.
Escorihuela M J,Kerr Y H,de Rosnay P et al.,2007.A simple model of the bare soil microwave emission at L-band.IEEE Transactions on Geoscience and Remote Sensing,45(7):1978-1987.doi:10.1109/TGRS.2007.894935
Fan L,Xiao Q,Wen J G et al.,2015.Mapping high-resolution soil moisture over heterogeneous cropland using multiresource remote sensing and ground observations.Remote Sensing,7(10):13273-13297.doi:10.3390/rs71013273
Goldberg D E,1989.Genetic Algorithms in Search,Optimization,and Machine Learning.Reading,Mass.:Addison-Wesley Professional.
Holmes T R H,De Rosnay P,De Jeu R et al.,2006.A new parameterization of the effective temperature for L band radiometry.Geophysical Research Letters,33(7):L07405.doi:10.1029/2006GL025724
Jackson T J,Schmugge T J,Wang J R,1982.Passive microwave sensing of soil moisture under vegetation canopies.Water Resources Research,18(4):1137-1142.doi:10.1029/WR018i004p01137
Jackson T J,Schmugge T J,1991.Vegetation effects on the microwave emission of soils.Remote Sensing of Environment,36(3):203-212.doi:10.1016/0034-4257(91)90057-D
Jackson T J,O’Neill P E,1990.Attenuation of soil microwave emission by corn and soybeans at 1.4 and 5 GHz.IEEE Transactions on Geoscience and Remote Sensing,28(5):978-980.doi:10.1109/36.58989
Kerr Y H,Waldteufel P,Richaume P et al.,2012.The SMOS soil moisture retrieval algorithm.IEEE Transactions on Geoscience and Remote Sensing,50(5):1384-1403.doi:10.1109/TGRS.2012.2184548
Kurum M,2013.Quantifying scattering albedo in microwave emission of vegetated terrain.Remote Sensing of Environment,129:66-74.doi:10.1016/j.rse.2012.10.021
Le Vine D M,Karam M A,1996.Dependence of attenuation in a vegetation canopy on frequency and plant water content.IEEE Transactions on Geoscience and Remote Sensing,34(5):1090-1096.doi:10.1109/36.536525.
Li Dazhi,Jin Rui,Che Tao et al.,2014.Soil moisture retrieval from airborne PLMR and MODIS products in the Zhangye oasis of middle stream of the Heihe River Basin,China.Advances in Earth Science,29(2):295-305.(in Chinese)
Li X,Cheng G D,Liu S M et al.,2013.Heihe watershed allied telemetry experimental research(HiWATER):scientific objectives and experimental design.Bulletin of the American Meteorological Society,94(8):1145-1160.doi:10.1175/BAMS-D-12-00154.1
Loew A,2008.Impact of surface heterogeneity on surface soil moisture retrievals from passive microwave data at the regional scale:the Upper Danube case.Remote Sensing of Environment,112(1):231-248.doi:10.1016/j.rse.2007.04.009
Ma M G,Chen Y Y,Wang X F et al.,2013.Hi WATER:Dataset of Soil Parameters in the Middle Reaches of the Heihe River Basin.Lanzhou,China:Heihe Plan Science Data Center.doi:10.3972/hiwater.147.2013.db
Mironov V L,Kosolapova L G,Fomin S V,2009.Physically and mineralogically based spectroscopic dielectric model for moist soils.IEEE Transactions on Geoscience and Remote Sensing,47(7):2059-2070.doi:10.1109/TGRS.2008.2011631
Njoku E G,Jackson T J,Lakshmi V et al.,2003.Soil moisture retrieval from AMSR-E.IEEE Transactions on Geoscience and Remote Sensing,41(2):215-229.doi:10.1109/TGRS.2002.808243
Pampaloni P,Paloscia S,1986.Microwave emission and plant water content:a comparison between field measurements and theory.IEEE Transactions on Geoscience and Remote Sensing,GE-24(6):900-905.doi:10.1109/TGRS.1986.289705
Panciera R,Walker J P,Kalma J D et al.,2009.Evaluation of the SMOS L-MEB passive microwave soil moisture retrieval algorithm.Remote Sensing of Environment,113(2):435-444.doi:10.1016/j.rse.2008.10.010
PardéM,Wigneron J P,Chanzy A et al.,2003.Retrieving surface soil moisture over a wheat field:comparison of different methods.Remote Sensing of Environment,87(2-3):334-344.doi:10.1016/j.rse.2003.08.002
Pellarin T,Wigneron J P,Calvet J C et al.,2003.Two-year global simulation of l-band brightness temperatures over land.IEEE Transactions on Geoscience and Remote Sensing,41(9):2135-2139.doi:10.1109/TGRS.2003.815417
Saleh K,Wigneron J P,Waldteufel P et al.,2007.Estimates of surface soil moisture under grass covers using L-band radiometry.Remote Sensing of Environment,109(1):42-53.doi:10.1016/j.rse.2006.12.002
SMAP,2012a.SMAP Validation Experiment 2012(SMAPVEX12)Experimental Plan.https://smapvex12.espaceweb.usherbrooke.ca/SMAPVEX12_Experiment_Plan.pdf.Updated 22 May 2012.
SMAP,2012b.SMAP Validation Experiment 2012(SMAPVEX12)Database Report.https://smapvex12.espaceweb.usherbrooke.ca/SMAPVEX12_Database_Report_final.pdf.Updated 18 December 2012.
Ulaby F T,Moore R K,Fung A K,1986.Microwave Remote Sensing vol.III,From Theory to Applications.London,UK:Artech House.
Ulaby F T,Tavakoli A,Thomas B A,1987.Microwave propagation constant for a vegetation canopy with vertical stalks.IEEE Transactions on Geoscience and Remote Sensing,GE-25(6):714-725.doi:10.1109/TGRS.1987.289741
Van De Griend A A,Owe M,De Ruiter J et al.,1996.Measurement and behavior of dual-polarization vegetation optical depth and single scattering albedo at 1.4-and 5-GHz microwave frequencies.IEEE Transactions on Geoscience and Remote Sensing,34(4):957-965.doi:10.1109/36.508412
Van de Griend A A,Wigneron J P,Waldteufel P,2003.Consequences of surface heterogeneity for parameter retrieval from1.4-GHz multiangle SMOS observations.IEEE Transactions on Geoscience and Remote Sensing,41(4):803-811.doi:10.1109/TGRS.2003.811083
Van De Griend A A,Wigneron J P,2004.The b-factor as a function of frequency and canopy type at H-polarization.IEEE Transactions on Geoscience and Remote Sensing,42(4):786-794.doi:10.1109/TGRS.2003.821889
Wang J R,Choudhury B J,1981.Remote sensing of soil moisture content,over bare field at 1.4 GHz frequency.Journal of Geophysical Research,86(C6):5277-5282.doi:10.1029/JC086i C06p05277
Wigneron J P,Chanzy A,Calvet J C et al.,1995a.A simple algorithm to retrieve soil moisture and vegetation biomass using passive microwave measurements over crop fields.Remote Sensing of Environment,51(3):331-341.doi:10.1016/0034-4257(94)00081-W
Wigneron J P,Calvet J C,Chanzy A et al.,1995b.A composite discrete-continuous approach to model the microwave emission of vegetation.IEEE Transactions on Geoscience and Remote Sensing,33(1):201-210.doi:10.1109/36.368208
Wigneron J P,Calvet J C,Kerr Y,1996.Monitoring water interception by crop fields from passive microwave observations.Agricultural and Forest Meteorology,80(2-4):122-194.doi:10.1016/0168-1923(95)02296-1
Wigneron J P,Laguerre L,Kerr Y H,2001.A simple parameterization of the L-band microwave emission from rough agricultural soils.IEEE Transactions on Geoscience and Remote Sensing,39(8):1697-1707.doi:10.1109/36.942548
Wigneron J P,Calvet J C,De Rosnay P et al.,2004a.Soil moisture retrievals from biangular L-band passive microwave observations.IEEE Geoscience and Remote Sensing Letters,1(4):277-281.doi:10.1109/LGRS.2004.834594
Wigneron J P,PardéM,Waldteufel P et al.,2004b.Characterizing the dependence of vegetation model parameters on crop structure,incidence angle,and polarization at L-band.IEEE Transactions on Geoscience and Remote Sensing,42(2):416-425.doi:10.1109/TGRS.2003.817976
Wigneron J P,Andersen S,Boutin J et al.,2006.Surface emission.In:M?tzler C(ed).Thermal Microwave Radiation:Applications for Remote Sensing.London,UK:The Institution of Engineering and Technology.
Wigneron J P,Kerr Y,Waldteufel P et al.,2007.L-band microwave emission of the biosphere(L-MEB)model:description and calibration against experimental data sets over crop fields.Remote Sensing of Environment,107(4):639-655.doi:10.1016/j.rse.2006.10.014
Yan S,Jiang L M,Chai L N et al.,2015.Calibration of the L-MEB model for croplands in HiWATER using PLMR observation.Remote Sensing,7(8):10878-10897.doi:10.3390/rs70810878