The International Soil Moisture Network: a data hosting facility for global in situ soil moisture measurements

Abstract. In situ measurements of soil moisture are invaluable for calibrating and validating land surface models and satellite-based soil moisture retrievals. In addition, long-term time series of in situ soil moisture measurements themselves can reveal trends in the water cycle related to climate or land cover change. Nevertheless, on a worldwide basis the number of meteorological networks and stations measuring soil moisture, in particular on a continuous basis, is still limited and the data they provide lack standardization of technique and protocol. To overcome many of these limitations, the International Soil Moisture Network (ISMN; http://www.ipf.tuwien.ac.at/insitu ) was initiated to serve as a centralized data hosting facility where globally available in situ soil moisture measurements from operational networks and validation campaigns are collected, harmonized, and made available to users. Data collecting networks share their soil moisture datasets with the ISMN on a voluntary and no-cost basis. Incoming soil moisture data are automatically transformed into common volumetric soil moisture units and checked for outliers and implausible values. Apart from soil water measurements from different depths, important metadata and meteorological variables (e.g., precipitation and soil temperature) are stored in the database. These will assist the user in correctly interpreting the soil moisture data. The database is queried through a graphical user interface while output of data selected for download is provided according to common standards for data and metadata. Currently (status May 2011), the ISMN contains data of 19 networks and more than 500 stations located in North America, Europe, Asia, and Australia. The time period spanned by the entire database runs from 1952 until the present, although most datasets have originated during the last decade. The database is rapidly expanding, which means that both the number of stations and the time period covered by the existing stations are still growing. Hence, it will become an increasingly important resource for validating and improving satellite-derived soil moisture products and studying climate related trends. As the ISMN is animated by the scientific community itself, we invite potential networks to enrich the collection by sharing their in situ soil moisture data.

[1]  R. Ward,et al.  Principles of Hydrology , 1968 .

[2]  G. Vachaud,et al.  Comparison of methods of calibration of a neutron probe by gravimetry or neutron-capture model , 1977 .

[3]  G. Vachaud,et al.  Temporal Stability of Spatially Measured Soil Water Probability Density Function , 1985 .

[4]  S. Prince,et al.  Water and Surface Energy Balance Modeling in Botswana , 1989 .

[5]  J. Mahfouf,et al.  Comparative Study of Various Formulations of Evaporations from Bare Soil Using In Situ Data , 1991 .

[6]  K. Vinnikov,et al.  Soil Moisture: Empirical Data and Model Results. , 1991 .

[7]  D. Fredlund,et al.  Soil Mechanics for Unsaturated Soils: Fredlund/Soil Mechanics for Unsaturated Soils , 1993 .

[8]  D. Fredlund,et al.  Soil Mechanics for Unsaturated Soils , 1993 .

[9]  T. Jackson,et al.  III. Measuring surface soil moisture using passive microwave remote sensing , 1993 .

[10]  R. Haverkamp,et al.  Bare-ground surface heat and water exchanges under dry conditions: Observations and parameterization , 1993 .

[11]  Scott A. Isard,et al.  A Soil Moisture Climatology of Illinois , 1994 .

[12]  Juha Hyyppä,et al.  Backscattering properties of boreal forests at the C- and X-bands , 1994, IEEE Trans. Geosci. Remote. Sens..

[13]  Spatial patterns of soil moisture for the FIFE study area derived from remotely sensed and ground data , 1995 .

[14]  Yann Kerr,et al.  Geographical, biological and remote sensing aspects of the hydrologic atmospheric pilot experiment in the sahel (HAPEX-Sahel) , 1995 .

[15]  Y. Xue,et al.  Use of midlatitude soil moisture and meteorological observations to validate soil moisture simulations with biosphere and bucket models , 1995 .

[16]  A. Robock,et al.  Scales of temporal and spatial variability of midlatitude soil moisture , 1996 .

[17]  Huug van den Dool,et al.  Analysis of model-calculated soil moisture over the United States (1931-1993) and applications to long-range temperature forecasts , 1996 .

[18]  Elfatih A. B. Eltahir,et al.  An analysis of the soil moisture‐rainfall feedback, based on direct observations from Illinois , 1997 .

[19]  Zong-Liang Yang,et al.  Validation of the Snow Submodel of the Biosphere-Atmosphere Transfer Scheme with Russian Snow Cover and Meteorological Observational Data , 1997 .

[20]  Jared Entin,et al.  Evaluation of the AMIP soil moisture simulations , 1998 .

[21]  B. McArthur,et al.  Baseline surface radiation network (BSRN/WCRP) New precision radiometry for climate research , 1998 .

[22]  A. J. Dolman,et al.  The Pilot Phase of the Global Soil Wetness Project , 1999 .

[23]  Guy W. Prettyman,et al.  Environmental Soil Physics , 1999 .

[24]  W. Wagner,et al.  A Method for Estimating Soil Moisture from ERS Scatterometer and Soil Data , 1999 .

[25]  Jared K. Entin,et al.  Optimal design of surface networks for observation of soil moisture , 1999 .

[26]  T. Jackson,et al.  Ground‐based investigation of soil moisture variability within remote sensing footprints During the Southern Great Plains 1997 (SGP97) Hydrology Experiment , 1999 .

[27]  M. Univer.  Ground-based investigation of soil moisture variability within remote sensing footprints during the Southern Great Plains 1997 (SGP97) Hydrology Experiment , 1999 .

[28]  A. Robock,et al.  Satellite remote sensing of soil moisture in Illinois, United States , 1999 .

[29]  P. Dirmeyer.  Using a global soil wetness dataset to improve seasonal climate simulation , 2000 .

[30]  Steven R. Evett,et al.  Soil Material, Temperature, and Salinity Effects on Calibration of Multisensor Capacitance Probes , 2000 .

[31]  A. Robock,et al.  The Global Soil Moisture Data Bank , 2000 .

[32]  Zong-Liang Yang,et al.  Simulations of a boreal grassland hydrology at Valdai, Russia: PILPS phase 2(d). , 2000 .

[33]  A. Robock,et al.  Temporal and spatial scales of observed soil moisture variations in the extratropics , 2000 .

[34]  Thomas J. Jackson,et al.  Polarimetric Scanning Radiometer (PSR) C band soil moisture retrieval in the Southern Great Plains 1999 experiment , 2001, IGARSS 2001. Scanning the Present and Resolving the Future. Proceedings. IEEE 2001 International Geoscience and Remote Sensing Symposium (Cat. No.01CH37217).

[35]  Jeffrey P. Walker,et al.  A methodology for surface soil moisture and vegetation optical depth retrieval using the microwave polarization difference index , 2001, IEEE Trans. Geosci. Remote. Sens..

[36]  W. Oechel,et al.  FLUXNET: A New Tool to Study the Temporal and Spatial Variability of Ecosystem-Scale Carbon Dioxide, Water Vapor, and Energy Flux Densities , 2001 .

[37]  R. Dickinson,et al.  The Representation of Snow in Land Surface Schemes: Results from PILPS 2(d) , 2001 .

[38]  Yann Kerr,et al.  Soil moisture retrieval from space: the Soil Moisture and Ocean Salinity (SMOS) mission , 2001, IEEE Trans. Geosci. Remote. Sens..

[39]  Thomas J. Jackson,et al.  Soil moisture retrieval using the C-band polarimetric scanning radiometer during the Southern Great Plains 1999 Experiment , 2002, IEEE Trans. Geosci. Remote. Sens..

[40]  D. Lettenmaier,et al.  A Long-Term Hydrologically Based Dataset of Land Surface Fluxes and States for the Conterminous United States* , 2002 .

[41]  Klaus Scipal,et al.  The global soil moisture archive 1992-2000 from ERS scatterometer data: first results , 2002, IEEE International Geoscience and Remote Sensing Symposium.

[42]  Thomas J. Jackson,et al.  Soil moisture retrieval from AMSR-E , 2003, IEEE Trans. Geosci. Remote. Sens..

[43]  R. Dickinson,et al.  Effects of frozen soil on soil temperature, spring infiltration, and runoff: Results from the PILPS 2(d) experiment at Valdai, Russia , 2003 .

[44]  José Martínez-Fernández,et al.  Temporal Stability of Soil Moisture in a Large‐Field Experiment in Spain , 2003 .

[45]  R. Koster,et al.  Global Soil Moisture from Satellite Observations, Land Surface Models, and Ground Data: Implications for Data Assimilation , 2004 .

[46]  K. Trenberth,et al.  A Global Dataset of Palmer Drought Severity Index for 1870–2002: Relationship with Soil Moisture and Effects of Surface Warming , 2004 .

[47]  Naoto Matsuura,et al.  DEVELOPMENT OF AN ADVANCED MICROWAVE SCANNING RADIOMETER (AMSR-E) ALGORITHM FOR SOIL MOISTURE AND VEGETATION WATER CONTENT , 2004 .

[48]  Jeffrey P. Walker,et al.  In situ measurement of soil moisture: a comparison of techniques | NOVA. The University of Newcastle's Digital Repository , 2004 .

[49]  A. Western,et al.  The Effect of Soil and Vegetation Parameters in the ECMWF Land Surface Scheme , 2004 .

[50]  Mingquan Mu,et al.  Forty‐five years of observed soil moisture in the Ukraine: No summer desiccation (yet) , 2004 .

[51]  Jeffrey P. Walker,et al.  THE GLOBAL LAND DATA ASSIMILATION SYSTEM , 2004 .

[52]  Xi Chen,et al.  Groundwater influences on soil moisture and surface evaporation , 2004 .

[53]  Matthias Drusch,et al.  Observation operators for the direct assimilation of TRMM microwave imager retrieved soil moisture , 2005 .

[54]  Barbara J. Bond,et al.  Precision and accuracy of three alternative instruments for measuring soil water content in two forest soils of the Pacific Northwest , 2005 .

[55]  A. Sterl,et al.  The ERA‐40 re‐analysis , 2005 .

[56]  Klaus Scipal,et al.  Validation of ERS scatterometer‐derived soil moisture data in the central part of the Duero Basin, Spain , 2005 .

[57]  P. Ciais,et al.  Europe-wide reduction in primary productivity caused by the heat and drought in 2003 , 2005, Nature.

[58]  J. Martínez-Fernández,et al.  Mean soil moisture estimation using temporal stability analysis , 2005 .

[59]  A. Robock,et al.  The Global Soil Moisture Data Bank - Benchmark Soil Moisture Observations , 2005 .

[60]  Naota Hanasaki,et al.  GSWP-2 Multimodel Analysis and Implications for Our Perception of the Land Surface , 2006 .

[61]  Thomas Foken,et al.  Area-Averaged Surface Fluxes Over the Litfass Region Based on Eddy-Covariance Measurements , 2006 .

[62]  W. Rawls,et al.  Soil Water Characteristic Estimates by Texture and Organic Matter for Hydrologic Solutions , 2006 .

[63]  Franz H. Berger,et al.  Latent heat fluxes simulated with a non-hydrostatic weather forecast model using actual surface properties from measurements and remote sensing , 2006 .

[64]  M. Drusch,et al.  Assimilation of Screen-Level Variables in ECMWF’s Integrated Forecast System: A Study on the Impact on the Forecast Quality and Analyzed Soil Moisture , 2007 .

[65]  Y. Kerr,et al.  L-band Microwave Emission of the Biosphere (L-MEB) Model: Description and calibration against experimental data sets over crop fields , 2007 .

[66]  Luca Brocca,et al.  Soil moisture spatial variability in experimental areas of central Italy , 2007 .

[67]  W. Wagner,et al.  Soil moisture from operational meteorological satellites , 2007 .

[68]  Mark Thyer,et al.  Goulburn River experimental catchment data set , 2007 .

[69]  Matthias Drusch,et al.  Initializing numerical weather prediction models with satellite‐derived surface soil moisture: Data assimilation experiments with ECMWF's Integrated Forecast System and the TMI soil moisture data set , 2007 .

[70]  J. M. Sabater,et al.  From near-surface to root-zone soil moisture using different assimilation techniques , 2007 .

[71]  H. Vereecken,et al.  Evaluation of a low-cost soil water content sensor for wireless network applications , 2007 .

[72]  Jean-Christophe Calvet,et al.  In situ soil moisture observations for the CAL/VAL of SMOS: the SMOSMANIA network , 2007, 2007 IEEE International Geoscience and Remote Sensing Symposium.

[73]  C. Albergel,et al.  An evaluation of ASCAT surface soil moisture products with in-situ observations in Southwestern France , 2008 .

[74]  T. Jackson,et al.  Temporal persistence and stability of surface soil moisture in a semi-arid watershed , 2008 .

[75]  R. Scott,et al.  Measuring soil moisture content non‐invasively at intermediate spatial scale using cosmic‐ray neutrons , 2008 .

[76]  C. Albergel,et al.  From near-surface to root-zone soil moisture using an exponential filter: an assessment of the method based on in-situ observations and model simulations , 2008 .

[77]  R. Knight,et al.  Soil Moisture Measurement for Ecological and Hydrological Watershed‐Scale Observatories: A Review , 2008 .

[78]  R. Jeu,et al.  Multisensor historical climatology of satellite‐derived global land surface moisture , 2008 .

[79]  Luca Brocca,et al.  On the estimation of antecedent wetness conditions in rainfall–runoff modelling , 2008 .

[80]  Klaus Scipal,et al.  A possible solution for the problem of estimating the error structure of global soil moisture data sets , 2008 .

[81]  Philippe Richaume,et al.  Evaluation of AMSR‐E soil moisture product based on ground measurements over temperate and semi‐arid regions , 2008 .

[82]  Peter E. Thornton,et al.  Improvements to the Community Land Model and their impact on the hydrological cycle , 2008 .

[83]  P. Rosnay,et al.  Multi-scale soil moisture measurements at the Gourma meso-scale site in Mali , 2009 .

[84]  Thierry Pellarin,et al.  Soil moisture mapping over West Africa with a 30-min temporal resolution using AMSR-E observations and a satellite-based rainfall product , 2009 .

[85]  C. Ottlé,et al.  The AMMA-CATCH experiment in the cultivated Sahelian area of south-west Niger – Investigating water cycle response to a fluctuating climate and changing environment , 2009 .

[86]  Y. Kerr,et al.  Soil moisture active and passive microwave products : intercomparison and evaluation over a Sahelian site , 2009 .

[87]  Klaus Scipal,et al.  An Improved Soil Moisture Retrieval Algorithm for ERS and METOP Scatterometer Observations , 2009, IEEE Transactions on Geoscience and Remote Sensing.

[88]  B. Hurk,et al.  A Revised Hydrology for the ECMWF Model: Verification from Field Site to Terrestrial Water Storage and Impact in the Integrated Forecast System , 2009 .

[89]  Niall P. Hanan,et al.  AMMA-CATCH studies in the Sahelian region of West-Africa: an overview , 2009 .

[90]  Frédéric Baup,et al.  The AMMA-CATCH Gourma observatory site in Mali: Relating climatic variations to changes in vegetation, surface hydrology, fluxes and natural resources , 2009 .

[91]  Luca Brocca,et al.  Antecedent Wetness Conditions based on ERS scatterometer data in support to rainfall-runoff modeling , 2009 .

[92]  Wade T. Crow,et al.  Performance Metrics for Soil Moisture Retrievals and Application Requirements , 2009 .

[93]  W. Mauser,et al.  The Upper Danube soil moisture validation site: measurements and activities , 2009 .

[94]  Frédéric Baup,et al.  ERS scatterometer surface soil moisture analysis of two sites in the south and north of the Sahel region of West Africa. , 2009 .

[95]  Thierry Pellarin,et al.  Hydrological modelling and associated microwave emission of a semi-arid region in South-western Niger , 2009 .

[96]  Thomas R. H. Holmes,et al.  An evaluation of AMSR–E derived soil moisture over Australia , 2009 .

[97]  Jiancheng Shi,et al.  The Soil Moisture Active Passive (SMAP) Mission , 2010, Proceedings of the IEEE.

[98]  B. Usowicz,et al.  Strategies for validating and directions for employing SMOS data, in the Cal-Val project SWEX (3275) for wetlands , 2010 .

[99]  S. Seneviratne,et al.  Recent decline in the global land evapotranspiration trend due to limited moisture supply , 2010, Nature.

[100]  Thomas J. Jackson,et al.  WindSat Global Soil Moisture Retrieval and Validation , 2010, IEEE Transactions on Geoscience and Remote Sensing.

[101]  Thomas J. Jackson,et al.  Validation of Advanced Microwave Scanning Radiometer Soil Moisture Products , 2010, IEEE Transactions on Geoscience and Remote Sensing.

[102]  Luca Brocca,et al.  ASCAT soil wetness index validation through in situ and modeled soil moisture data in central Italy , 2010 .

[103]  Yi Y. Liu,et al.  Error characterisation of global active and passive microwave soil moisture datasets. , 2010 .

[104]  A. Loew.  A dynamic approach for validating coarse scale satellite soil moisture products , 2010 .

[105]  S. Seneviratne,et al.  Investigating soil moisture-climate interactions in a changing climate: A review , 2010 .

[106]  Luca Brocca,et al.  Spatial‐temporal variability of soil moisture and its estimation across scales , 2010 .

[107]  W. Crow,et al.  Estimating Spatial Sampling Errors in Coarse-Scale Soil Moisture Estimates Derived from Point-Scale Observations , 2010 .

[108]  W. Wagner,et al.  Cross-evaluation of modelled and remotely sensed surface soil moisture with in situ data in southwestern France , 2010 .

[109]  Gert König-Langlo,et al.  The Baseline Surface Radiation Network , 2012 .

[110]  T. Ferré,et al.  Nature's neutron probe: Land surface hydrology at an elusive scale with cosmic rays , 2010 .

[111]  W. Wagner,et al.  Soil moisture estimation through ASCAT and AMSR-E sensors: An intercomparison and validation study across Europe , 2011 .

[112]  S. Seneviratne,et al.  Drought and ecosystem carbon cycling , 2011 .

[113]  A. Robock,et al.  A New International Network for in Situ Soil Moisture Data , 2011 .

[114]  S. Seneviratne,et al.  Soil moisture monitoring for climate research: Evaluation of a low‐cost sensor in the framework of the Swiss Soil Moisture Experiment (SwissSMEX) campaign , 2011 .

[115]  Yi Y. Liu,et al.  Developing an improved soil moisture dataset by blending passive and active microwave satellite-based retrievals , 2011 .

[116]  Robert M. Parinussa,et al.  Error Estimates for Near-Real-Time Satellite Soil Moisture as Derived From the Land Parameter Retrieval Model , 2011, IEEE Geoscience and Remote Sensing Letters.

[117]  Jaakko Seppänen,et al.  L-Band Radiometer Observations of Soil Processes in Boreal and Subarctic Environments , 2012, IEEE Transactions on Geoscience and Remote Sensing.

[118]  Eric A. Rosenberg,et al.  A Long-Term Hydrologically Based Dataset of Land Surface Fluxes and States for the Conterminous United States: Update and Extensions* , 2002 .