Abstract
Drought, a highly detrimental natural disaster, poses significant threats to both human populations, wildlife, and vegetation. Traditional methods of monitoring soil moisture levels rely on ground-based measurements from meteorological stations. However, these stations often lack comprehensive coverage in certain agricultural areas, necessitating the use of alternative methods such as satellite remote sensing. This technique provides a reliable means of measuring soil moisture, a critical factor in effective agricultural management. This paper investigates variations in soil moisture and drought using data from the Cyclone Global Navigation Satellite System (CYGNSS) and the Soil Moisture Active and Passive (SMAP) system. To evaluate the accuracy of these data products, we compared both datasets with the Global Land Data Assimilation System (GLDAS) NOAH model from 2018 to 2019. Our findings reveal a strong correlation between the datasets and the model, with Pearson correlation coefficients (r) and Root Mean Square Errors (RMSE) of approximately r = 0.98 and RMSE = 0.03 for SMAP, and r = 0.97 and RMSE = 0.02 for CYGNSS, respectively. We further compared these measurement datasets with drought indicators such as the Standardized Precipitation Index over three months (SPI3), the Normalized Difference Vegetation Index (NDVI), and Total Water Storage (TWS). The correlation coefficients between SMAP and the three indicators (NDVI, SPI3, and TWS) were 0.93, 0.84, and 0.047, respectively, while the coefficients between CYGNSS and the same indicators were 0.86, 0.78, and 0.56, respectively. All the variables also exhibited significant p-values. Despite minor differences, the results demonstrate excellent agreement. Our findings underscore the sensitivity of space-based sensors to drought conditions, highlighting their effectiveness as tools for detecting and monitoring drought (e.g. agricultural drought), particularly in the short term.
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References
AghaKouchak A (2014) A baseline probabilistic drought forecasting framework using Standardized Soil Moisture Index: application to the 2012 United States drought. Hydrol Earth Syst Sci 18(7):2485–2492. https://doi.org/10.5194/hess-18-2485-2014
AghaKouchak A, Nakhjiri N (2012) A near real-time satellite-based global drought climate data record. Environ Res Lett 7(4):044037. https://doi.org/10.1088/1748-9326/7/4/044037
AghaKouchak A, Farahmand A, Melton FS, Teixeira J, Anderson MC, Wardlow BD, Hain CR (2015) Remote sensing of drought: progress, challenges and opportunities. Rev Geophys 53:452–480. https://doi.org/10.1002/2014RG000456
Al-Khaldi MM, Johnson JT, O’Brien AJ, Balenzano A, Mattia F (2019) Time-series retrieval of soil moisture using CYGNSS. IEEE Trans Geosci Remote Sens 57(7):4322–4331
Anderson MC, Hain C, Wardlow B, Pimstein A, Mecikalski JR, Kustas WP (2011) Evaluation of drought indices based on thermal remote sensing of evapotranspiration over the continental United States. J Clim 24(8):2025–2044. https://doi.org/10.1175/2010JCLI3812.1
Bai et al (2018) Assessment of the SMAP-derived soil water deficit index (SWDI-SMAP) as an agricultural drought index in China. Remote Sens 10(8):1302. https://doi.org/10.3390/rs10081302
Beguería S, Vicente-Serrano SM, Reig F, Latorre B (2014) Standardized precipitation evapotranspiration index (SPEI) revisited: parameter fitting, evapotranspiration models, tools, datasets and drought monitoring. Int J Climatol 34:3001–3023
Bittelli M, Valentino R, Salvatorelli F, Rossi Pisa P (2012) Monitoring soil-water and displacement conditions leading to landslide occurrence in partially saturated clays. Geomorphology 173–174:161–173
Bolten JD, Crow WT, Zhan X, Jackson TJ, Reynolds CA (2010) Evaluating the utility of remotely sensed soil moisture retrievals for operational agricultural drought monitoring. IEEE J Sel Top Appl Earth Obs Remote Sens 3(1):57–66. https://doi.org/10.1109/JSTARS.2009.2037163
Brocca L, Melone F, Moramarco T, Wagner W, Naeimi V, Bartalis Z, Hasenauer S (2010) Improving runoff prediction through the assimilation of the ASCAT soil moisture product. Hydrol Earth Syst Sci 14:1881–1893
Brocca L, Ponziani F, Moramarco T, Melone F, Berni N, Wagner W (2012) Improving landslide forecasting using ASCAT-derived soil moisture data: a case study of the Torgiovannetto landslide in central Italy. Remote Sens 4:1232–1244
Calabia A, Molina I, Jin SG (2019) Soil moisture content from GNSS reflectometry using dielectric permittivity from fresnel reflection coefficients. Remote Sens 12(1):122. https://doi.org/10.3390/rs12010122
Chan S, Bindlish R, O’Neill PE, Njoku E, Jackson T, Colliander A, Chen F, Burgin M, Dunbar S, Piepmeier J et al (2016) Assessment of the SMAP passive soil moisture product. IEEE Trans Geosci Remote Sens 54:1–14
Chew CC, Small EE (2018) Soil moisture sensing using spaceborne GNSS reflections: comparison of CYGNSS reflectivity to SMAP soil moisture. Geophys Res Lett 45(9):4049–4057
Crow W T, Berg A A, Cosh M H, Loew A, Mohanty B P, Panciera R, Rosnay P, Ryu D, Walker J P (2012) Upscaling sparse ground—based soil moisture observations for the validation of coarse-resolution satellite soil moisture products. Rev Geophys 50
Davenport ML, S E NICHOLSON, (1993) On the relation between rainfall and the normalized difference vegetation index for diverse vegetation types in East Africa. Int J Remote Sens 14(12):2369–2389. https://doi.org/10.1080/01431169308954042
Easterling D (2013) Global data sets for analysis of climate extremes. Extrem Changing Clim 65:347–361. https://doi.org/10.1007/978-94-007-4479-012
Edokossi et al (2020) GNSS-reflectometry and remote sensing of soil moisture: a review of measurement techniques, methods, and applications. Remote Sens 12:614. https://doi.org/10.3390/rs12040614
Enenkel M, Steiner C, Mistelbauer T, Dorigo W, Wagner W, See L, Atzberger C, Schneider S, Rogenhofer E (2016) A combined satellite-derived drought indicator to support humanitarian aid organizations. Remote Sens 8:340
Entekhabi D et al (2004) The hydrosphere state (Hydros) satellite mission: an earth system pathfinder for global mapping of soil moisture and land freeze/thaw. IEEE Trans Geosci Remote Sens 42(10):2184–2195. https://doi.org/10.1109/TGRS.2004.834631
Entekhabi D et al (2010) The soil moisture active passive (SMAP) mission. Proc IEEE 98(5):704–716. https://doi.org/10.1109/JPROC.2010.2043918
Eswar R, Das NN, Poulsen C, Behrangi A, Swigart J, Svoboda M, Entekhabi D, Yueh S, Doorn B, Entin J (2018) SMAP Soil Moisture Change as an Indicator of Drought Conditions. Remote Sens 10(5). https://doi.org/10.3390/rs10050788
Field CB (2012) Managing the risks of extreme events and disasters to advance climate change adaptation: special report of the intergovernmental panel on climate change. Cambridge University Press, Cambridge, p 2012
Forootan E et al (2019) Understanding the global hydrological droughts of 2003–2016 and their relationships with teleconnections. Sci Total Environ 650:2587–2604. https://doi.org/10.1016/j.scitotenv.2018.09.231
Gebrehiwot T et al (2011) Spatial and temporal assessment of drought in the Northern highlands of Ethiopia. Int J Appl Earth Observ Geoinform 13(3):309–321. https://doi.org/10.1016/j.jag.2010.12.002
Gleason S, Adjrad M Sensing ocean, ice and land reflected signals from space: results from the UK-DMC GPS reflectometry experiment (2005) In: Proceedings of the 18th international technical meeting of the satellite division of the institute of navigation, Long Beach, CA, USA, 13–16 Sept 2005
Godfray HC, Beddington JR, Crute IR, Haddad L, Lawrence D, Muir JF, Pretty J, Robinson S, Thomas SM, Toulmin C (2010) Food security: the challenge of feeding 9 billion people. Science 327(5967):812–818. https://doi.org/10.1126/science.1185383
Hao Z, AghaKouchak A (2013) Multivariate standardized drought index: a parametric multi-index model. Adv Water Res 57:12–18. https://doi.org/10.1016/j.advwatres.2013.03.009
Hofmann-Wellenhof B, Lichtenegger H, Wasle E (2008) GNSS-global navigation satellite systems: GPS, GLONASS, Galileo and More, 1st edn. Springer, Wien, p 518
Ji L, Peters AJ (2003) Assessing vegetation response to drought in the northern great plains using vegetation and drought indices. Remote Sens Environ 87(1):85–98. https://doi.org/10.1016/S0034-4257(03)00174-3
Jia Y, Savi P (2017) Sensing soil moisture and vegetation using GNSS-R polarimetric measurement. Adv Space Res 59:858–869
Jin S, Komjathy A (2010) GNSS reflectometry and remote sensing: new objectives and results. Adv Space Res 46:111–117
Kim J, Hogue T (2012) Improving spatial soil moisture representation through integration of AMSR-E and MODIS products. IEEE Trans Geosci Remote Sens 50(2):446–460
Kim H, Lakshmi V (2018) Use of cyclone global navigation satellite system (CyGNSS) observations for estimation of soil moisture. Geophys Res Lett 45:8272–8282
Kongoli C, P Romanov, R Ferraro (2012) Snow cover monitoring from remote sensing satellites. In: Remote sensing of drought: innovative monitoring approaches, pp. 359–386, CRC Press
Koster RD, Mahanama SPP, Livneh B, Lettenmaier D, Reichle RH (2010) Skill in streamflow forecasts derived from large-scale estimates of soil moisture and snow. Nat Geosci 3:613–616
Lawal S, Lennard C, Hewitson B (2019) Response of southern African vegetation to climate change at 1.5 and 2.0 global warming above the pre-industrial level. Clim Serv 16:100134
Molina I, Calabia A, Jin S, Edokossi K, Wu X (2022) Calibration and validation of CYGNSS reflectivity through wetlands’ and deserts’ dielectric permittivity and validation with SMAP data. Remote Sens 14:3262. https://doi.org/10.3390/rs14143262
Njoku EG, Jackson TJ, Lakshmi V, Chan TK, Nghiem SV (2003) Soil moisture retrieval from AMSR-E. IEEE Trans Geosci Remote Sens 41(2):215–229. https://doi.org/10.1109/TGRS.2002.808243
Parry M, Canziani OF, Palutikof JP, van der Linden PJ, Hanson CE (2007) Climate change, 2007 impacts, adaptation and vulnerability. Cambridge University Press, Cambridge, p 4
Rahmani A, Golian S, Brocca L (2016) Multiyear monitoring of soil moisture over Iran through satellite and reanalysis soil moisture products. Int J Appl Earth Obs Geoinf 48:85–95
Raziei T, Saghafian B, Paulo AA et al (2009) Spatial patterns and temporal variability of drought in western Iran. Water Resour Manag 23:439–455. https://doi.org/10.1007/s11269-008-9282-4
Reichle RH, Koster RD, Dong J, Berg AA (2004) Global soil moisture from satellite observations, land surface models, and ground data: implications for data assimilation. J Hydrometeorol 5(3):430–442
Rodell M, Famiglietti J (2002) The potential for satellite-based monitoring of groundwater storage changes using GRACE: The high plains aquifer, central US. J Hydrol 263(1):245–256
Rossi S, Niemeyer S (2012) Drought monitoring with estimates of the fraction of absorbed photosynthetically-active radiation (fAPAR) derived from MERIS. In: Wardlow B, Anderson M, Verdin J (eds) Remote sensing for drought: innovative monitoring approaches. CRC Press, Boca Raton, pp 95–116
Sánchez N, González-Zamora Á, Piles M, Martínez-Fernández J (2016) A new soil moisture agricultural drought index (SMADI) integrating MODIS and SMOS products: a case of study over the Iberian Peninsula. Remote Sens 8:287
Seager R, Hoerling M, Schubert S, Wang H, Lyon B, Kumar A, Nakamura J, Henderson N (2015) Causes of the 2011–14 California drought. J Clim 28(18):6997–7024. https://doi.org/10.1175/JCLI-D-14-00860.1
Sheffield J, Goteti G, Wen F, Wood E (2004) A simulated soil moisture-based drought analysis for the United States. J Geophys Res 109:D24108. https://doi.org/10.1029/2004JD005182
Sheffield J, Wood E, Roderick M (2012) Little change in global drought over the past 60 years. Nature 491(7424):435–438
Singh H, Thompson A (2016) Effect of antecedent soil moisture content on soil critical shear stress in agricultural watersheds. Geoderma 262:165–173
Sorooshian S et al (2011) Advanced concepts on remote sensing of precipitation at multiple scales. Bull Am Meteorol Soc 92(10):1353–1357
Takada M, Mishima Y, Natsume S (2009) Estimation of surface soil properties in peatland using ALOS/PALSAR. Landscape Ecol Eng 5(1):45–58
Velpuri NM, Senay GB, Morisette JT (2016) Evaluating new SMAP Soil moisture for drought monitoring in the rangelands of the US high plains. Rangelands 38(4):183–190. https://doi.org/10.1016/j.rala.2016.06.002
Vicente-Serrano SM, López-Moreno JI (2005) Hydrological response to different time scales of climatological drought: an evaluation of the Standardized Precipitation Index in a mountainous Mediterranean basin. Hydrol Earth Syst Sci 9(5):523–533
Vicente-Serrano SM, Beguería S, López-Moreno JI (2010) A multiscalar drought index sensitive to global warming: the standardized precipitation evapotranspiration index. J Clim 23:1696–1718
Wagner W, Dorigo W, de Jeu R, Fernandez D, Benveniste J, Haas E, Ertl M (2012) Fusion of active and passive microwave observations to create an essential climate variable data record on soil moisture. ISPRS annals of the photogrammetry, remote sensing and spatial information sciences, 1. https://doi.org/10.5194/isprsannals-I-7-315-2012
Wang L, Qu JJ (2009) Satellite remote sensing applications for surface soil moisture monitoring: a review. Front Earth Sci Chin 3(2):237–247
Wu XR, Jin SG (2020) Models and theoretical analysis of SoOP circular polarization bistatic scattering for random rough surfaces. Remote Sens 12:1506
Wu Q, Liu H, Wang L, Deng C (2016) Evaluation of AMSR2 soil moisture products over the contiguous United States using in situ data from the International soil moisture network. Int J Appl Earth Obs Geoinf 45:187–199
Wu X, Song Y, Xu J, Duan Z, Jin SG (2021a) Bistatic scattering simulations of circular and linear polarizations over land surface for signals of opportunity reflectometry. Geosci Lett 8:11. https://doi.org/10.1186/s40562-021-00182-y
Wu X, Ma W, Xia J, Bai W, Jin S, Calabia A (2021b) Spaceborne GNSS-R soilmoisture retrieval: status, development opportunities, and challenges. Remote Sens 13:45. https://doi.org/10.3390/rs13010045
Zhu Q, Luo Y, Yue-Ping Xu, Tian Ye, Yang T (2019) Satellite soil moisture for agricultural drought monitoring: assessment of SMAP-derived soilwater deficit index in Xiang river basin. China Remote Sens 11:362. https://doi.org/10.3390/rs11030362
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Financial supports of this work were provided by Shanghai Leading Talent Project (Grant No. E056061).
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Data curation, K.E.; funding acquisition, S.J.; methodology, K.E., S.J. and I.M.; computation, K.E. and U.M.; supervision, S.J. and I.M.; writing—original draft, K.E.; writing—review and editing, S.J., I.M., A.C. and I.U. All authors have read and agreed to the published version of the manuscript.
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Edokossi, K., Jin, S., Mazhar, U. et al. Monitoring the drought in Southern Africa from space-borne GNSS-R and SMAP data. Nat Hazards (2024). https://doi.org/10.1007/s11069-024-06546-9
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DOI: https://doi.org/10.1007/s11069-024-06546-9