1. DISASTER RISK REDUCTION CONFERENCE WARSZAWA, 15-16.10.2015 Urszula Somorowska Wydział Geografii i Studiów Regionalnych Uniwersytet Warszawski usomorow@uw.edu.pl Extreme stages of the soil wetness conditions over Poland: dynamics and risks

2. Extreme stages of the soil wetness conditions over Poland: dynamics and risks DISASTER RISK REDUCTION CONFERENCE WARSZAWA, 15-16.10.2015 Outline 1. Why important is the Soil Water ? 2. Questions addressed, data and methods 3. Seasonal and interannual variability of Soil Water Occurance of extreme wetness conditions in particular years Soil Drought Propagation

3. Background… importance of subsurface water storage study Droughts and heat waves are a major hazard for food & water security, impacting human & ecosystem health. Droughts and heat waves are a major hazard for food & water security, impacting human & ecosystem health. Over the last decades, heat waves and rainless periods have been observed across different regions of the world, with several locations, including Poland, experiencing soil moisture deficits. Over the last decades, heat waves and rainless periods have been observed across different regions of the world, with several locations, including Poland, experiencing soil moisture deficits. Orth, Seneviratne, 2015 Monthly anomaly of soil water storage over Europe in selected years August 2003 --- drought conditions over Poland August 2010 --- wet conditions over Poland

4. Main objective The main objective is to infer dynamics of soil water storage over Poland using selected soil water storage indicator. The main objective is to infer dynamics of soil water storage over Poland using selected soil water storage indicator. Study is based on terrestrial water storage data obtained from the Global Land Data Assimilation System (GLDAS). Study is based on terrestrial water storage data obtained from the Global Land Data Assimilation System (GLDAS). Mean monthly spatial patterns of soil water storage were generated over Poland Temporal evolution of at a daily time scale was evaluated for central Poland

5. Questions addressed (1) what is spatio-temporal evolution of SWS? (1) what is spatio-temporal evolution of SWS? (2) how shallow subsurface water storage is depleting in summer in respond to meteorological drought ? (2) how shallow subsurface water storage is depleting in summer in respond to meteorological drought ? Case study focused on territory of Poland Case study focused on territory of Poland Long time series of SWS Long time series of SWS At least of moderate spatial resolution At least of moderate spatial resolution

6. Temporal evolution of SWS is detected by ground measurements, sattelite images, LSM Soil moisture ground monitoring stations are still scarce, and the existing systems are not standardized in terms of measurement techniques, data format, access, etc Soil moisture ground monitoring stations are still scarce, and the existing systems are not standardized in terms of measurement techniques, data format, access, etc Satellite based remote sensing images have the potential to overcome the observational gap of monitoring terrestrial water storage changes however long term data are usually not available. Satellite based remote sensing images have the potential to overcome the observational gap of monitoring terrestrial water storage changes however long term data are usually not available. Land Surface Models provides long-term simulations of land Surface stages, including Soil Moisture as an indicator. Land Surface Models provides long-term simulations of land Surface stages, including Soil Moisture as an indicator. GLDAS - Global Land Data Assimilation System GLDAS - Global Land Data Assimilation System

7. GLDAS Dane pozyskane z systemu GLDAS (Global Land Data Assimilation System) w ramach projektu NEWS (ang. NASA’s Energy and Water Cycle Study)

8. Noah model : Noah model : Four Soil layers: Four Soil layers: 0-10cm, 0-10cm, 10-40cm, 10-40cm, 40-100cm, 40-100cm, 100-200cm 100-200cm Years: 2000-2015 0.25  x0.25 , ~~23km 0.25  x0.25 , ~~23km Temporal resolution monthly, 3h Temporal resolution monthly, 3h Data and methods GLDAS data Spatial data Digital resources (MPHP) GEOPROCESSING of Data using ArcGIS 10.2 tools and iterative models In Model Builder.

10. Seasonal and interannual dynamics  Recharge of the soil water appears usually in months from October till February, whereas from March till September depletion of soil water storage is observed.  In particular years this usual rhythm might be disturbed by meteorological conditions.  In the examined period, the driest conditions were detected in August 2003, July 2006 and along the year 2014, and in 2015 (partially evaluated). Especially wet conditions appeared in May and June 2010.

11. Mean monthly soil water storage soil layer 0-50cm, November-April

12. Mean monthly soil water storage soil layer 0-50cm, May-October

13. Mean monthly soil water storage 2000-2014, black line, Poland Kolorem czarnym oznaczono wartości średnie miesięczne dla wielolecia.

14. Drought criterion, soil moisture percentile value of 20% central Poland

15. Daily SWS, central Poland, 2000-2015 drought criterion of soil moisture – red line

16. SWS 0-50 cm, 2003, 2006, 2010

17. Conclusions (1) GLDAS provides global access to soil moisture data. Application of such a data significantly refines the image of spatial structure of soil water storage, when comparing to ground sparce information. Monthly time series show a contrasting response of terrestrial water storage at interannual scale, reflecting impact of variable precipitation recharge and summer heat waves. Signals of drought appear across the whole country, however most often they occur in lowlands from east, through central Poland, to the west.

18. Conclusions (2) Seasonal cycle comprises recharge of SWS in months October-February/March and depletion from April- September. Sometimes extreme wet stages might occur in summer as a result of intensive precipitation recharge (y. 2010) In particular years, as a result of variable precipitation and evapotranspiration, propagation of drought might have different duration. Symptoms of drought might appear in winter half of the year.

19. Thank You !