{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,17]],"date-time":"2026-09-17T17:33:58Z","timestamp":1789666438219,"version":"4.0.1"},"reference-count":41,"publisher":"MDPI AG","issue":"10","license":[{"start":{"date-parts":[[2015,10,15]],"date-time":"2015-10-15T00:00:00Z","timestamp":1444867200000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100000104","name":"National Aeronautics and Space Administration","doi-asserted-by":"publisher","award":["12-SMAP12-0011"],"award-info":[{"award-number":["12-SMAP12-0011"]}],"id":[{"id":"10.13039\/100000104","id-type":"DOI","asserted-by":"publisher"}]},{"name":"Chinese Scholarship Council","award":["CSC No. 201406270032"],"award-info":[{"award-number":["CSC No. 201406270032"]}]}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Remote Sensing"],"abstract":"<jats:p>Satellite-derived soil moisture products have become an important data source for the study of land surface processes and related applications. For satellites with sun-synchronous orbits, these products are typically derived separately for ascending and descending overpasses with different local acquisition times. Moreover, diurnal variations in land surface conditions, and the extent to which they are accurately characterized in retrieval algorithms, lead to distinct systematic and random error characteristics in ascending versus descending soil moisture products. Here, we apply two independent evaluation techniques (triple collocation and direct comparison against sparse ground-based observations) to quantify (correlation-based) accuracy differences in satellite-derived surface soil moisture acquired at different local acquisition times. The orbits from different satellites are separated into two overpass categories: AM (12:00 a.m. to 11:59 a.m. Local Solar Time) and PM (12:00 p.m. to 11:59 p.m. Local Solar Time). Results demonstrate how patterns in the accuracy of AM versus PM retrieval products obtained from a variety of active and passive microwave satellite sensors vary according to land cover and across satellite products with different local acquisition times.<\/jats:p>","DOI":"10.3390\/rs71013448","type":"journal-article","created":{"date-parts":[[2015,10,15]],"date-time":"2015-10-15T12:44:06Z","timestamp":1444913046000},"page":"13448-13465","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":50,"title":["The Impact of Local Acquisition Time on the Accuracy of Microwave Surface Soil Moisture Retrievals over the Contiguous United States"],"prefix":"10.3390","volume":"7","author":[{"ORCID":"https:\/\/orcid.org\/0000-0002-0201-7717","authenticated-orcid":false,"given":"Fangni","family":"Lei","sequence":"first","affiliation":[{"name":"School of Resource and Environmental Sciences, Wuhan University, Wuhan 430072, China"},{"name":"USDA ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Wade","family":"Crow","sequence":"additional","affiliation":[{"name":"USDA ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Huanfeng","family":"Shen","sequence":"additional","affiliation":[{"name":"School of Resource and Environmental Sciences, Wuhan University, Wuhan 430072, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Robert","family":"Parinussa","sequence":"additional","affiliation":[{"name":"Water Research Centre, School of Civil and Environmental Engineering, University of New South Wales, Sydney, NSW 2052, Australia"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Thomas","family":"Holmes","sequence":"additional","affiliation":[{"name":"USDA ARS Hydrology and Remote Sensing Laboratory, Beltsville, MD 20705, USA"},{"name":"Science Systems and Applications, Incorporated, Greenbelt, MD 20705, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2015,10,15]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"1138","DOI":"10.1126\/science.1100217","article-title":"Regions of strong coupling between soil moisture and precipitation","volume":"305","author":"Koster","year":"2004","journal-title":"Science"},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"215","DOI":"10.1109\/TGRS.2002.808243","article-title":"Soil moisture retrieval from AMSR-E","volume":"41","author":"Njoku","year":"2003","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_3","doi-asserted-by":"crossref","first-page":"1999","DOI":"10.1109\/TGRS.2008.2011617","article-title":"An improved soil moisture retrieval algorithm for ERS and METOP scatterometer observations","volume":"47","author":"Naeimi","year":"2009","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_4","doi-asserted-by":"crossref","first-page":"666","DOI":"10.1109\/JPROC.2010.2043032","article-title":"The SMOS mission: New tool for monitoring key elements of the global water cycle","volume":"98","author":"Kerr","year":"2010","journal-title":"Proc. IEEE"},{"key":"ref_5","doi-asserted-by":"crossref","first-page":"704","DOI":"10.1109\/JPROC.2010.2043918","article-title":"The soil moisture active passive (SMAP) mission","volume":"98","author":"Entekhabi","year":"2010","journal-title":"Proc. IEEE"},{"key":"ref_6","doi-asserted-by":"crossref","first-page":"4256","DOI":"10.1109\/TGRS.2010.2051035","article-title":"Validation of advanced microwave scanning radiometer soil moisture products","volume":"48","author":"Jackson","year":"2010","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_7","unstructured":"Pampaloni, P., and Paloscia, S. (2000). Microwave Radiometry and Remote Sensing of the Earth\u2019s Surface and Atmosphere, VSP. [1st ed.]."},{"key":"ref_8","doi-asserted-by":"crossref","first-page":"4210","DOI":"10.1109\/LGRS.2012.2211993","article-title":"A study of SMOS RFI over North America","volume":"10","author":"Aksoy","year":"2013","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_9","doi-asserted-by":"crossref","first-page":"589","DOI":"10.1109\/JSTARS.2014.2336664","article-title":"Refinement of SMOS multiangular brightness temperature toward soil moisture retrieval and its analysis over reference targets","volume":"8","author":"Zhao","year":"2015","journal-title":"IEEE J. Sel. Topics Appl. Earth Observ. Remote Sens."},{"key":"ref_10","doi-asserted-by":"crossref","first-page":"127","DOI":"10.1016\/j.rse.2005.12.004","article-title":"Impact of rain interception by vegetation and mulch on the L-band emission of natural grass","volume":"101","author":"Saleh","year":"2006","journal-title":"Remote Sens. Environ."},{"key":"ref_11","doi-asserted-by":"crossref","first-page":"67","DOI":"10.1109\/LGRS.2008.2000714","article-title":"Effects of dew on the radiometric signal of a grass field at L-band","volume":"6","author":"Escorihuela","year":"2009","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_12","doi-asserted-by":"crossref","first-page":"1544","DOI":"10.1109\/TGRS.2011.2178158","article-title":"Comparisons of evening and morning SMOS passes over the Midwest United States","volume":"50","author":"Rowlandson","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_13","doi-asserted-by":"crossref","first-page":"703","DOI":"10.1016\/j.rse.2008.11.011","article-title":"An evaluation of AMSR-E derived soil moisture over Australia","volume":"113","author":"Draper","year":"2009","journal-title":"Remote Sens. Environ."},{"key":"ref_14","doi-asserted-by":"crossref","first-page":"6229","DOI":"10.1002\/2014GL061322","article-title":"Extended triple collocation: Estimating errors and correlation coefficients with respect to an unknown target","volume":"41","author":"McColl","year":"2014","journal-title":"Geophys. Res. Lett."},{"key":"ref_15","doi-asserted-by":"crossref","first-page":"F01002","DOI":"10.1029\/2007JF000769","article-title":"Multisensor historical climatology of satellite-derived global land surface moisture","volume":"113","author":"Owe","year":"2008","journal-title":"J. Geophys. Res.: Earth Surf."},{"key":"ref_16","doi-asserted-by":"crossref","first-page":"399","DOI":"10.1007\/s10712-008-9044-0","article-title":"Global soil moisture patterns observed by space borne microwave radiometers and scatterometers","volume":"29","author":"Wagner","year":"2008","journal-title":"Surv. Geophys."},{"key":"ref_17","doi-asserted-by":"crossref","first-page":"2605","DOI":"10.5194\/hess-14-2605-2010","article-title":"Error characterisation of global active and passive microwave soil moisture datasets","volume":"14","author":"Dorigo","year":"2010","journal-title":"Hydrol. Earth Syst. Sc."},{"key":"ref_18","doi-asserted-by":"crossref","first-page":"288","DOI":"10.1016\/j.rse.2013.06.013","article-title":"Estimating root mean square errors in remotely sensed soil moisture over continental scale domains","volume":"137","author":"Draper","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_19","doi-asserted-by":"crossref","first-page":"1384","DOI":"10.1109\/TGRS.2012.2184548","article-title":"The SMOS soil moisture retrieval algorithm","volume":"50","author":"Kerr","year":"2012","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_20","doi-asserted-by":"crossref","first-page":"614","DOI":"10.1016\/j.rse.2014.07.013","article-title":"Global-scale comparison of passive (SMOS) and active (ASCAT) satellite based microwave soil moisture retrievals with soil moisture simulations (MERRA-Land)","volume":"152","author":"Wigneron","year":"2014","journal-title":"Remote Sens. Environ."},{"key":"ref_21","first-page":"D03109","article-title":"Continental-scale water and energy flux analysis and validation for the North American Land Data Assimilation System project phase 2 (NLDAS-2): 1. Intercomparison and application of model products","volume":"117","author":"Xia","year":"2012","journal-title":"J. Geophys. Res.: Atmos."},{"key":"ref_22","doi-asserted-by":"crossref","first-page":"D22","DOI":"10.1029\/2002JD003296","article-title":"Implementation of Noah land surface model advances in the National Centers for Environmental Prediction operational mesoscale Eta model","volume":"108","author":"Ek","year":"2003","journal-title":"J. Geophys. Res.: Atmos."},{"key":"ref_23","doi-asserted-by":"crossref","first-page":"D15107","DOI":"10.1029\/2011JD015633","article-title":"An intercomparison of available soil moisture estimates from thermal infrared and passive microwave remote sensing and land surface modeling","volume":"116","author":"Hain","year":"2011","journal-title":"J. Geophys. Res.: Atmos."},{"key":"ref_24","unstructured":"Soil Climate Analysis Network Data and Products, Available online: http:\/\/www.wcc.nrcs.usda.gov\/scan\/."},{"key":"ref_25","doi-asserted-by":"crossref","first-page":"2073","DOI":"10.1175\/2007JTECHA930.1","article-title":"The USDA natural resources conservation service soil climate analysis network (SCAN)","volume":"24","author":"Schaefer","year":"2007","journal-title":"J. Atmos. Oceanic Tech."},{"key":"ref_26","unstructured":"U.S. Climate Reference Network, Available online: http:\/\/www.ncdc.noaa.gov\/crn\/."},{"key":"ref_27","doi-asserted-by":"crossref","first-page":"121","DOI":"10.1109\/LGRS.2005.843983","article-title":"Analytical derivation of the vegetation optical depth from the microwave polarization difference index","volume":"2","author":"Meesters","year":"2005","journal-title":"IEEE Geosci. Remote Sens. Lett."},{"key":"ref_28","doi-asserted-by":"crossref","first-page":"380","DOI":"10.1109\/TGRS.2003.817195","article-title":"A preliminary survey of radio-frequency interference over the US in Aqua AMSR-E data","volume":"42","author":"Li","year":"2004","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_29","unstructured":"MODIS Vegetation Indices Monthly L3 Global 0.05Deg CMG, Available online: https:\/\/lpdaac.usgs.gov\/dataset_discovery\/modis\/modis_products_table\/mod13c2."},{"key":"ref_30","doi-asserted-by":"crossref","first-page":"832","DOI":"10.1175\/2010JHM1223.1","article-title":"Performance metrics for soil moisture retrievals and application requirements","volume":"11","author":"Entekhabi","year":"2010","journal-title":"J. Hydrometeorol."},{"key":"ref_31","doi-asserted-by":"crossref","first-page":"L19501","DOI":"10.1029\/2004GL020938","article-title":"Bias reduction in short records of satellite soil moisture","volume":"31","author":"Reichle","year":"2004","journal-title":"Geophys. Res. Lett."},{"key":"ref_32","doi-asserted-by":"crossref","first-page":"1423","DOI":"10.1175\/2010JHM1285.1","article-title":"Estimating spatial sampling errors in coarse-scale soil moisture estimates derived from point-scale observations","volume":"11","author":"Miralles","year":"2010","journal-title":"J. Hydrometeorol."},{"key":"ref_33","doi-asserted-by":"crossref","first-page":"7755","DOI":"10.1029\/97JC03180","article-title":"Toward the true near-surface wind speed: Error modeling and calibration using triple collocation","volume":"103","author":"Stoffelen","year":"1998","journal-title":"J. Geophys. Res.: Ocean."},{"key":"ref_34","doi-asserted-by":"crossref","first-page":"L24403","DOI":"10.1029\/2008GL035599","article-title":"A possible solution for the problem of estimating the error structure of global soil moisture data sets","volume":"35","author":"Scipal","year":"2008","journal-title":"Geophys. Res. Lett."},{"key":"ref_35","doi-asserted-by":"crossref","first-page":"3135","DOI":"10.5194\/hess-15-3135-2011","article-title":"The impact of land surface temperature on soil moisture anomaly detection from passive microwave observations","volume":"15","author":"Parinussa","year":"2011","journal-title":"Hydrol. Earth Syst. Sc."},{"key":"ref_36","doi-asserted-by":"crossref","first-page":"240","DOI":"10.1016\/j.rse.2013.02.017","article-title":"Spatial distribution and possible sources of SMOS errors at the global scale","volume":"133","author":"Leroux","year":"2013","journal-title":"Remote Sens. Environ."},{"key":"ref_37","doi-asserted-by":"crossref","first-page":"1293","DOI":"10.1175\/JHM-D-13-0158.1","article-title":"Evaluation of assumptions in soil moisture triple collocation analysis","volume":"15","author":"Yilmaz","year":"2014","journal-title":"J. Hydrometeorol."},{"key":"ref_38","doi-asserted-by":"crossref","first-page":"RG2002","DOI":"10.1029\/2011RG000372","article-title":"Upscaling sparse ground-based soil moisture observations for the validation of coarse-resolution satellite soil moisture products","volume":"50","author":"Crow","year":"2012","journal-title":"Rev. Geophys."},{"key":"ref_39","doi-asserted-by":"crossref","unstructured":"Efron, B., and Tibshirani, R.J. (1994). An Introduction to the Bootstrap, Chapman and Hall\/CRC. [1st ed.].","DOI":"10.1201\/9780429246593"},{"key":"ref_40","doi-asserted-by":"crossref","first-page":"3855","DOI":"10.1109\/TGRS.2014.2386142","article-title":"Impact of diurnal variation in vegetation water content on radar backscatter from maize during water stress","volume":"53","author":"Judge","year":"2015","journal-title":"IEEE Trans. Geosci. Remote Sens."},{"key":"ref_41","doi-asserted-by":"crossref","first-page":"063571-1","DOI":"10.1117\/1.JRS.6.063571","article-title":"Effect of dew on aircraft-based passive microwave observations over an agricultural domain","volume":"6","author":"Du","year":"2012","journal-title":"J. Appl. Remote Sens."}],"container-title":["Remote Sensing"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/www.mdpi.com\/2072-4292\/7\/10\/13448\/pdf","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2025,10,11]],"date-time":"2025-10-11T20:50:09Z","timestamp":1760215809000},"score":1,"resource":{"primary":{"URL":"https:\/\/www.mdpi.com\/2072-4292\/7\/10\/13448"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[2015,10,15]]},"references-count":41,"journal-issue":{"issue":"10","published-online":{"date-parts":[[2015,10]]}},"alternative-id":["rs71013448"],"URL":"https:\/\/doi.org\/10.3390\/rs71013448","relation":{},"ISSN":["2072-4292"],"issn-type":[{"value":"2072-4292","type":"electronic"}],"subject":[],"published":{"date-parts":[[2015,10,15]]}}}