http://hydrology.irpi.cnr.it

MERGING MULTIPLE SOIL MOISTURE PRODUCTS FOR IMPROVING THE

ACCURACY IN RAINFALL ESTIMATION THROUGH SM2RAIN

22 nd Sept. 2016

Luca Brocca, Angelica Tarpanelli, Luca Ciabatta, Christian Massari, Paolo Filippucci, Amarnath Giriraj,

Wolfgang Wagner

3rd Satellite Soil Moisture Validation and Application Workshop

Remote sensing of rainfall

RAINGAUGE DENSITY1 degree resolution

CPC dataset

0

2

1

510

REVISIT TIME

# SATELLITES

The GPM constellation

Synthetic data

Observed data

The retrieval approach used in GPM is based on a “top-down” approach providing an estimate of the INSTANTANEOUS RAINFALL RATE at the satellite overpass

At least, 10 passes per day are needed for obtaining satisfactory performance in estimating 1-day rainfall

WHY GPM IS SO SUCCESSFUL IN BUILDING A CONSTELLATION?

SM2RAIN: a new “bottom-up” approach!

SM2RAIN is a new “bottom-up” approach (Brocca et al., 2014 JGR) for estimating the ACCUMULATED RAINFALL from satellite (and in situ) soil moisture observations

precipitationsurface runoff

evapotranspiration

drainage

soil water capacity

relative saturation

Inverting for p(t):= soil depth X porosity

Assuming: + +ONLY during rainfall

Soil water balance equation

SM2RAIN algorithm

1 equation, 3 parameters (Z,a,b)…very SIMPLE!

An example with SMAP soil moisture data

Red dots: SMAP Level-2 retrievals (descending)Blue histogram: gauge-based rainfall time series

(Western U.S.)

A lot of rain: SM goes up a lotA little rain: SM goes up a little

Just published on WRR: 1st SM2RAIN application to SMAP observations

R² map(1-degree, 5-day)

SM2RAIN application to multiple products

SM2RAIN application to multiple products

Metop-A

Blu: MetopA+MetopBRed: MetopABlack: rainfall

Rainfall events not detected by Metop-A only and correctly identified by using both Metop-A and Metop-B

Metop-B

What is the potential of a constellation?

A soil moisture constellation!

What is the benefit coming from the integration of multiple

satellite soil moisture product for SM2RAIN application?

How to perform the integration? Which

product/algorithm/band/orbit to include?

What spatial/temporal sampling?

Ground and satellite rainfall datasets

India Meteorological Department (IMD) rainfall dataset (1901-currrent)

Currently (freely) available satellite soil moisture products

2012 2013 2014 2015 2016 J A J O J A J O J A J O J A J O J A J OASCAT Metop-A

ASCAT Metop-B

AMSR2

SMOS

SMAP

RapidScat

Period: 1-April-2015 31-December-2015 Spatial/temporal resolution: 0.25°/1-day Integration at RAINFALL LEVEL (minimization RMSE) ASCAT: Metop-A+Metop-B AMSR2: LPRM algorithm, X-band AMSR2&SMOS: separately asc. and desc. orbits RapidScat: separately HH and VV polarization

A similar analysis was also carried out in Italy, results available at http://dx.doi.org/10.13140/RG.2.2.24296.67848

Performance of single products5-day correlation maps

Low performance in northern India (Himalaya) ASCAT, SMAP and AMSR2 performs very good (median R>0.78) RapidScat is performing less good, likely due to vegetation SMOS is affected by RFI (mainly ascending orbit) during 2015 in India

Merging multiple SM prods: R and RMSE3-day and 5-day correlation maps

Rainfall timeseries

Underestimation of large rainfall events due to the saturation problem

Overestimation of low rain rates due to noise in satellite soil moisture products

Comparison with GPM early and final run

1. Significantly better performance than GPM products, also of the final run (gauge-corrected)

2. Product potentially available in near real-time (large potential for flood, drought, landslide applications)

GPMfinal run

GPMearly run

SM2RAIN-multiple SM

# Journal Year Reference Short description

1 GRL 2013 Brocca, L., Melone, F., Moramarco, T., Wagner, W. (2013). A new method for rainfall estimation through soil moisture observations. Geophysical Research Letters, 40(5), 853-858.

First application of SM2RAIN to in situ and satellite data (some locations)

2 JGR 2014Brocca, L., Ciabatta, L., Massari, C., Moramarco, T., Hahn, S., Hasenauer, S., Kidd, R., Dorigo, W., Wagner, W., Levizzani, V. (2014). Soil as a natural rain gauge: estimating global rainfall from satellite soil moisture data. Journal of Geophysical Research, 119(9), 5128-5141.

SM2RAIN application to ASCAT, AMSR-E and SMOS soil moisture products on a global scale

3 AWR 2014Massari, C., Brocca, L., Moramarco, T., Tramblay, Y., Didon Lescot, J.-F. (2014). Potential of soil moisture observations in flood modelling: estimating initial conditions and correcting rainfall. Advances in Water Resources, 74, 44-53.

Improving runoff prediction by using SM2RAIN-derived rainfall applied to in situ observations (France)

4 JHH 2015Brocca, L., Massari, C., Ciabatta, L., Moramarco, T., Penna, D., Zuecco, G., Pianezzola, L., Borga, M., Matgen, P., Martínez-Fernández, J. (2015). Rainfall estimation from in situ soil moisture observations at several sites in Europe: an evaluation of SM2RAIN algorithm. Journal of Hydrology and Hydromechanics, 63(3), 201-209.

Detailed analysis of SM2RAIN algorithm in 10 sites over Europe (testing of different formulations)

5 JHM 2015 Ciabatta, L., Brocca, L., Massari, C., Moramarco, T., Puca, S., Rinollo, A., Gabellani, S., Wagner, W. (2015). Integration of satellite soil moisture and rainfall observations over the Italian territory. Journal of Hydrometeorology, 16(3), 1341-1355.

Integration of top-down (TRMM 3B42RT) and bottom-up (SM2RAIN) approaches over Italy

6 JAG 2016Ciabatta, L., Brocca, L., Massari, C., Moramarco, T., Gabellani, S., Puca, S., Wagner, W. (2016). Rainfall-runoff modelling by using SM2RAIN-derived and state-of-the-art satellite rainfall products over Italy. International Journal of Applied Earth Observation and Geoinformation, 48, 163-173.

Improving runoff prediction by using SM2RAIN-derived rainfall applied to satellite observations (4 basins in Italy)

7 JSTARS 2016 Brocca, L., Massari, C., Ciabatta, L., Wagner, W., Stoffelen, A. (2016). Remote sensing of terrestrial rainfall from Ku-band scatterometers. IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing, 9(1), 533-539.

Application of SM2RAIN to Ku-band scatterometer data (RapidSCAT) in central Italy

8 ATMRES 2016Abera, W., Brocca, L., Rigon, R. (2016). Comparative evaluation of different satellite rainfall estimation products and bias correction in the Upper Blue Nile (UBN) basin. Atmospheric Research, 178-179, 471-483.

Application of SM2RAIN to ESA CCI soil moisture product in Ethiopia

9 WRR 2016 Koster, R.D., Brocca, L., Crow, W.T., Burgin, M.S., De Lannoy, G.J.M. (2016). Precipitation Estimation Using L-Band and C-Band Soil Moisture Retrievals. Water Resources Research, in press.

Application of SM2RAIN to SMAP, SMOS and ASCAT on a global scale

10 JGR Minor rev

Brocca, L., Pellarin, T., Crow, W.T., Ciabatta, L., Massari, C., Ryu, D., Su, C.-H., Rudiger, C., Kerr, Y. (...). Rainfall estimation by inverting SMOS soil moisture estimates: a comparison of different methods over Australia. submitted to Journal of Geophysical Research.

Application of three methods for rainfall estimation from SMOS in Australia

11 HESS Subm.Abera, W., Formetta, G., Brocca, L., Rigon, R. (...). Water budget modelling of the Upper Blue Nile basin using the JGrass-NewAge model system and satellite data. Hydrology and Earth System Sciences Discussion, in review, doi:10.5194/hess-2016-290. http://dx.doi.org/10.5194/hess-2016-290

Use of SM2RAIN rainfall for water budget modelling in ungauged areas

12 JoH Minor rev.

Ciabatta, L., Marra, A.C., Panegrossi, G., Casella, D., Sanò, P., Dietrich, S., Massari, C., Brocca, L. (...) Analysis of daily rainfall over Italy from satellite microwave-based precipitation products. submitted to Journal of Hydrology.

Integration of top-down (CDRD-PNPR) and bottom-up (SM2RAIN) approaches over Italy, an update

13 JSTARS Subm.Brocca, L., Crow, W.,T. Ciabatta, L., Massari, C., de Rosnay, P., Enenkel, M., Hahn, S., Amarnath, G., Camici, S., Tarpanelli, A., Wagner, W. (...). A review of the applications of scatterometer soil moisture data. submitted to IEEE Journal of Selected Topics in Applied Earth Observations and Remote Sensing.

Review of scatterometer soil moisture applications with recent results of SM2RAIN

1 TCD 2014 Pan, X., Yu, Q., and You, Y. (2014). Role of rainwater induced subsurface flow in water-level dynamics and thermoerosion of shallow thermokarst ponds on the Northeastern Qinghai–Tibet Plateau, The Cryosphere Discuss., 8, 6117-6146.

Application of SM2RAIN for estimating rainfall from in situ soil moisture observations

2 HESS Subm.Beck, H. E., van Dijk, A. I. J. M., Levizzani, V., Schellekens, J., Miralles, D. G., Martens, B., and de Roo, A. (…). MSWEP: 3-hourly 0.25° global gridded precipitation (1979–2015) by merging gauge, satellite, and reanalysis data. Hydrology and Earth System Sciences Discussion, in review, doi:10.5194/hess-2016-236.

Independent global scale assessment of SM2RAIN-ASCAT rainfall product

FOR FURTHER INFORMATIONURL: http://hydrology.irpi.cnr.it/people/l.brocca

URL IRPI: http://hydrology.irpi.cnr.it

SM2RAIN-derived RAINFALL dataset from ASCAT,

0.5°/daily, 2007-2015, global, fr

eely available

DOI:10.13140/RG.2.1.4434.8563