RSMN – 4 Years of In-situ and Satellite Soil Moisture … · 2018. 9. 13. · RSMN – 4 Years of...

RSMN – 4 Years of in-situ and satellite soil moisture observations

in Romania

A. Diamandi, E. Mateescu, O. Nicola, E. Luca, R. Chiritescu

National Meteorological Administration (NMA)

Satellite Soil Moisture Validation and Applications Workshop - Vienna 19-20 September 2017 1

Outline

• 1. Motivation• 2. NMA weather station network• 3. ASSIMO Project• 4. RSMN (sites, selection, probes, stations) • 5. Datasets• 6. Results• 7. Next


Motivation

• We have identified a need for soil moisture products in various areas:– Agriculture (crop monitoring, yield forecasting),– Hydrology (flood forecast, reservoir management)– Fire risk

• Kickstart satellite soil moisture activities in Romania• To build a long-term soil moisture record• To evaluate existing & future satellite soil moisture

products for specific application areas• To build expertise• To better understand uses needs


Agriculture in Romania: Facts & Figures(2016)

• 13,3 Mil. ha agricultural land (55.9% of total)• Share in the GDP = 4.64%, the highest in the

EU-28 and 3.5 times the EU average • Jobs: 23.1 % (1,951,719) of the labor force

(8,449,000)• Income = 6,675 Mil. Euro


Soil moisture observations

• Agro-meteorological measurements:– At the locations of 55 weather stations, in nearby

crop fields– Temporal resolution: 10 days– Depths: 20, 50, 100 cm

• However, continuous measurement of soil moisture was all but nonexistent before 2014


The Weather Station Network


The surface observation network: 160 weather stations

Project ASSIMO - Assessment of Satellite Derived Soil Moisture Products over Romania

2013-2016Program for Research-Development-Innovation for Space Technology and Advanced Research – STAR

Romanian Space Agency

“The overall goal of the project is to pave the way for the utilisation ofsatellite derived soil moisture products in Romania, by creating theframework for the validation and evaluation of actual & future satellitemicrowave soil moisture derived products, demonstrating its value and bydeveloping the necessary expertise for successfully tackling implementationsin the relevant Societal Benefit Areas (as they were defined in GEOSS)”


RSMN – The Romanian Soil Moisture Network

• RSMN is made up of a fixed and a mobile component

• Fixed component: 20 sites (2014/2015 - ) at weather station locations

• Mobile component: 24 mobile stations• 15 mobile stations have been deployed in 2015-

2016 in Prahova county• The mobile stations have been redeployed to

weather station locations at the end of 2016


RSMN - Current configuration


As of the 5th of December 2016: 44 sites (20 fixed + 24 mobile stations)

Soil Moisture Stations – The Probes

• Both fixed & mobile stations use the Decagon 5TM sensor• Probes at 0-5 cm depth• TDR (Time Domain Reflectometry) probe• Measures dielectric permittivity & temperature• Volumetric soil moisture calculated with Topp’s formula• Factory calibration used (probes have not been calibrated for the type

of soil at the respective site)


Measurement Volumetric soil moisture Temperature

Accuracy ± 0.03 m³/m³ ± 1° C

Resolution 0.0008 m³/m³ 0.1° C

Domain 0 – 1 m³/m³ - 40° C la + 50° C

Soil Moisture Stations – The Fixed Component(1)

– 5TM probes wired to the existing weather station data loggers (older versions need a SDI-12 module)

– Data collected in the operational data flow and stored in the NMA database– Available to ISMN as of 2015


Fixed station – block diagram

Soil Moisture Stations – The Fixed Component(2)


The Soil Moisture Stations -The Mobile Component(1)

• Mobile Station = Data logger (Arduino based) + Soil moisture probe (Decagon 5TM) • Manufacturer = Meteo Romania/ASSIMO Project• Cost (materials): ~ 500 Eur.


Mobile station – block diagram

The Soil Moisture Stations -The Mobile Component(2)


Site Selection

• 1. Low RFI• 2. Altitude < 600m• 3. Land cover: minimal wetlands, minimal

urban/rural, uniform cover• 4. Soil type: not predominantly loamy• Much of the work here inspired by Simone

Bircher’s et all. article (“A soil moisture and temperature network for SMOS validation in Western Denmark”)


RFI


Radio frequency interference map 2013

Satellite Datasets

Satellite Orbit LST Dataset/Version Spatial Provider

SMOS ascending 06:00 L3/P11p 25 km/EASE2 SMOS-BEC

SMAP descending 06:00 L3_S_MP/V3 080 36 km/EASE2 NASA/ASF

ASCAT both 06:00* H08 – SM-OBS-2** 1 km H-SAF


(*): Nearest overpass to 06:00 (**): Derived by disaggregating the global-scale product SM-OBS-1 (25 km resolution),

to 1-km sampling SMOS-BEC: SMOS Barcelona Expert Centre on Radiometric Calibration and Ocean

Salinity Period: 01/03/2015 – 31/07/2017

In situ Datasets

Year Local Time Period No. of sites

2015 06:00 01/03-30/11 20

2016 06:00 01/03-31/10 20

2017 06:00 01/04-31/07 31


Variables: Soil moisture Rainfall

Data Processing & Evaluation Method

• In situ soil moisture data filtered for:– values > 1 m-3 m-3 and < 0 m-3 m-3

– outliers (abnormal jumps)• One cannot compare a point measurement with the

satellite footprint (soil moisture variability, large scale mismatch)

• Use a linear average of the in situ observations of all stations were compared with the averaged satellite soil moisture products of all grids within RSMN– spatial averaging can reduce the spatial noise– method used in many validation studies


RSMN v ASCAT/SMOS/SMAP 2015-2017 (The Tables)


ASCATYear BIAS RMSE R ubRMSE N

2015 0.119 0.136 0.520 0.066 214

2016 0.117 0.126 0.450 0.046 185

SMAPYear BIAS RMSE R ubRMSE N

2015 0.067 0.080 0.760 0.044 91

2016 0.066 0.075 0.780 0.037 77

2017 0.082 0.084 0.783 0.024 113

SMOSYear BIAS RMSE R ubRMSE N

2015 -0.004 0.036 0.785 0.035 186

2016 0.048 0.042 0.643 0.039 165

2017 0.080 0.084 0.781 0.024 119

SMOS, SMAP well within missions requirements of 0.04 m-3 /m-3 (2015-2017), and ASCAT (0.05 m-3 /m-3) in 2016

RSMN v ASCAT 2015-2016 (The Plots)


2015 2016

RSMN v SMAP 2015-2017 (The Plots)


2015 2016

2017

RSMN v SMOS 2015-2017 (The Plots)


2015 2016

2017

Who has been using RSMN data?• Zeng, J., Chen, K.-S., Bi, H., & Chen, Q. (2016). A Preliminary Evaluation of

the SMAP Radiometer Soil Moisture Product Over United States and Europe Using Ground-Based Measurements. IEEE Transactions on Geoscience and Remote Sensing, 54(8), 4929–4940. https://doi.org/10.1109/TGRS.2016.2553085

• A. Al-Yaari, J.-P.Wigneron, Y. Kerr, N. Rodriguez-Fernandez, P.E. O'Neill, T.J. Jacksond, G.J.M. De Lannoy, A. Al Bitar b, A.Mialonb, P. Richaume, J.P. Walker, A.Mahmoodi, S. Yuehg. Evaluating soil moisture retrievals from ESA's SMOS and NASA's SMAP brightness temperature datasets. Remote Sensing of Environment 193 (2017) 257–273


https://doi.org/10.1109/TGRS.2016.2553085

What’s next?

• Add more sites (fixed) to the network: 15 – 20• Test:

– Interferometric reflectometry measurements (GNSS) of soil moisture

– COSMOS

• Adapt/test existing products for Agriculture and Hydrology


Thank You!

Andrei [email protected]


RSMN – 4 Years of In-situ and Satellite Soil Moisture … · 2018. 9. 13. · RSMN – 4 Years of...

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