DISASTER RISK REDUCTION CONFERENCEWARSZAWA, 15-16.10.2015

Urszula SomorowskaUrszula SomorowskaWydział Geografii i Studiów RegionalnychWydział Geografii i Studiów Regionalnych

Uniwersytet WarszawskiUniwersytet Warszawskiusomorow@uw.edu.plusomorow@uw.edu.pl

Extreme stages of the soil wetness conditions

over Poland: dynamics and risks

Extreme stages of the soil wetness conditions

over Poland: dynamics and risks

DISASTER RISK REDUCTION CONFERENCEWARSZAWA, 15-16.10.2015

Outline1. Why important is the Soil Water ?2. Questions addressed, data and methods3. Seasonal and interannual variability of Soil Water Occurance of extreme wetness conditions in particular years Soil Drought Propagation

Background…Background…importance of subsurface water importance of subsurface water

storage study storage study Droughts and heat waves are a major hazard Droughts and heat waves are a major hazard

for food & water security, for food & water security, impacting human & impacting human & ecosystem health.ecosystem health.

Over the last decadeOver the last decadess, heat waves , heat waves and rainless and rainless periods periods have been observed across different have been observed across different regions of the world, with several locationsregions of the world, with several locations, , including Poland, including Poland, experiencing soil moisture experiencing soil moisture deficits.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

Main objectiveMain objective

The main objective is to infer The main objective is to infer dynamics of soil dynamics of soil water storage water storage over Polandover Poland using using selected soil selected soil water storage indicator.water storage indicator.

SStudy is based on terrestrial water storagetudy is based on terrestrial water storage data obtained from the Global data obtained from the Global Land Data Assimilation System (GLDAS).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

Questions addressedQuestions addressed (1) (1) what is spatio-temporal evolution of what is spatio-temporal evolution of

SWS?SWS? (2) how shallow subsurface water (2) how shallow subsurface water

storage is depleting in summer in storage is depleting in summer in respond to meteorological drought respond to meteorological drought ??

Case study focused on territory of Case study focused on territory of PolandPoland

Long time series of SWSLong time series of SWS At least of moderate spatial resolutionAt least of moderate spatial resolution

Temporal evolution of SWS is Temporal evolution of SWS is detected bydetected by

ground measurements, sattelite images, ground measurements, sattelite images, LSMLSM Soil moisture Soil moisture ground ground monitoring stations are still monitoring stations are still

scarce, and the existingscarce, and the existing systems are not systems are not standardized in terms of measurement standardized in terms of measurement techniques, data format, access, etctechniques, data format, access, etc

Satellite based remote sensing Satellite based remote sensing images images have the have the potential to overcome the observational gap of potential to overcome the observational gap of monitoring terrestrial watermonitoring terrestrial water storage changes storage changes however long term data are usually not available. however long term data are usually not available.

Land Surface Models provides long-term Land Surface Models provides long-term simulations of land Surface stages, including Soil simulations of land Surface stages, including Soil Moisture as an indicator.Moisture as an indicator.

GLDAS - Global Land Data Assimilation SystemGLDAS - Global Land Data Assimilation System

GLDAS GLDAS

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

Noah model : Noah model : Four Soil layers:Four Soil layers: 0-10cm, 0-10cm, 10-40cm, 10-40cm, 40-100cm,40-100cm, 100-200cm100-200cm Years: 2000-2015 0.250.25x0.25x0.25, ~~23km, ~~23km Temporal resolution monthly, Temporal resolution monthly,

3h 3h

Data and methodsData and methods GLDAS data Spatial data

Digital resources (MPHP)

GEOPROCESSING of Data using ArcGIS 10.2 tools and iterative models In Model Builder.

Seasonal and interannual dynamicsSeasonal 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.

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

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

Mean monthly soil water storage

2000-2014, black line, Poland

Kolorem czarnym oznaczono wartości średnie miesięczne dla wielolecia.

Drought criterion, soil moisture percentile Drought criterion, soil moisture percentile value of 20%value of 20%

central Polandcentral Poland

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

line line

SWS 0-50 cm, 2003, SWS 0-50 cm, 2003, 2006, 20102006, 2010

Conclusions (1)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.

Conclusions (2)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.

Thank You !Thank You !