Longest dry spell and Number of dry spells (catchment)
1 General
1.1 Description
The indicators are derived from precipitation which is defined as the sum of liquid and solid
precipitation and expressed as volume equivalent of liquid precipitation.
Two indicators are given to describe the dry spells (periods with consecutive dry days) statistics
during 30-year periods in the data:
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Longest dry spell: the largest number of consecutive days during which the precipitation is
less than 1 mm/day
Number of dry spells: the number of dry spells with a length of more than 5 days during
which precipitation is less than 1 mm/day
Note that the indicators are based on daily precipitation data as processed by each hydrological model
and therefore, the indicators differ for the different hydrological models.
For the reference period (1971-2000) the absolute values are given, while for the future periods the
relative changes are provided.
Note that the precipitation data is based on bias-corrected climate model output which was further
processed by the hydrological model (by applying a height correction and a spatial interpolation).
For the reference period (1971-2000) the absolute values are given, while for the future periods the
relative changes are provided.
1.2 Units
Reference period: longest dry spell (no. of days), number of dry spells (no. of periods)
Future periods:
percentage change relative to the reference period (%)
1.3 Links
Link to downloadable indicator data:
http://swicca.climate.copernicus.eu/indicator-interface/graphs-and-download/
Link to map-view:
http://swicca.climate.copernicus.eu/indicator-interface/maps/
1.4 Data format
Downloadable data comes in Excel-format. There is one Excel sheet per period. Within each sheet, the
different ensemble members are named following the structure INSTITUTE_RCM_GCM_RCP (see
Table 1). The catchments for which the data has been downloaded are labelled by a specific number in
the column “subid” which stands for sub-basin identifier. Empty Excel cells indicate non-valid or
missing data.
Note: All members that share the same combination of hydrological model, RCM and GCM have the
same values in the reference period since all of them share the same historical data.
1
1.5 Keywords
Flux, precipitation, dry spell
1.6 Contact
Further information on calculation of indicators:
Thomas Bosshard ([email protected])
Further information on hydrological model runs:
see contact details in Table 1
2 Dataset coverage
2.1 Geographic area
The data is given for irregular polygons representing catchments of E-HYPEv3.1.2. The model
domain encompasses the European landmass (see Figure 1).
Figure 1 M ap showing the model domain of E-HYPEv3.1.2
2.2 Temporal resolution
All indicators are derived from daily data. The indicators themselves represent statistics over a long
period and do not have a temporal resolution.
2.3 Time period
Using the date format YEAR-MONTH-DAY, the different periods are defined as follows:
Reference period:
1971-01-01 to 2000-12-31
Future periods:
2011-01-01 to 2040-12-31
2041-01-01 to 2070-12-31
2071-01-01 to 2100-12-31
If a projection did not cover the full period 2071-2100 (see Table 1), the indicators were calculated
based on the remaining years in the period.
2.4 Spatial resolution
Irregular catchment polygons, median catchment size 215 km2 .
2
3 Usage
3.1 License conditions
None
3.2 Citation(s)
Y. Hundecha et al. 2016. A regional parameter estimation scheme for a pan-European multi-basin
model. Journal of Hydrology: Regional Studies, 6(2016), 90-111., doi:10.1016/j.ejrh.2016.04.002
4 Lineage statement
4.1 Original data source
The climate impact indicators are based on hydrological impact modelling using the hydrological
model E-HYPEv3.1.2. The hydrological modelling was done for SWICCA with an ensemble of biascorrected climate model data provided by the EU FP7 project IMPACT2C (grant agreement 282746).
More information on the climate-model ensemble used (for instance model selection procedures,
uncertainties, adjustments) can be found here:
http://impact2c.hzg.de/imperia/md/content/csc/projekte/impact2c_d5.1_fin.pdf
Within the project IMPACT2C, the original RCM output data has been spatially interpolated, adjusted
to the standard Gregorian calendar and has partly been bias-corrected. More details can be found here:
http://impact2c.hzg.de/imperia/md/content/csc/projekte/impact2c_d4.1.pdf
The dataset covers the ensemble members given in Table 1. The ensemble comprises three
Representative Concentration Pathways (RCP) to cover a range of policy scenarios: a mitigation
scenario (RCP2.6), a stabilization scenario (RCP4.5) and a high greenhouse gas scenario (RCP8.5).
Note that the SWICCA indicators on catchment resolution are provided for an ensemble using one
hydrological model (E-HYPEv3.1.2).
Further, note that the indicators for “Dry Spells” are meant to show the data including the influence of
E-HYPE’s pre-processing of precipitation(i.e. height correction and spatial interpolation).
The full ensemble of time series from the model runs is stored at SMHI and the original daily timeseries of some essential climate variables can be downloaded in the SWICCA interface.
4.2 Tools used in production of indicators
Indices have been computed using CDO (https://code.zmaw.de/projects/cdo) and its ECA indices
library (https://code.zmaw.de/projects/cdo/embedded/cdo_eca.pdf)
5 Data quality
SWICCA uses state-of-the-art, quality controlled data to produce this indicator, but the user should
note that model performance can vary substantially by location and indicator and not all indicators can
be evaluated at a pan-European scale. The quality of the E-HYPE pan-European hydrological model
can be perused here: http://hypeweb.smhi.se/europehype/model-performance/ and is summarized in
Hundecha et al. (2016).
3
Contact
Model input / forcing
[email protected]
E-HYPE 2.1
Hydrological
model
Table 1 Table of all available ensemble members for the indicators. The abbreviations in M odel input/forcing stand for
various elements of the modeling chain: Representative Concentration Pathway (RCP), Global Circulation M odel (GCM ) and
Regional Climate M odel (RCM ).
RCP
GCM
EC-EARTH
2.6
MPI-ESM-LR
EC-EARTH
EC-EARTH
4.5 HadGEM2-ES
MPI-ESM-LR
CM5A
EC-EARTH
8.5 EC-EARTH
HadGEM2-ES
MPI-ESM-LR
RCM
RCA4
REMO2009
RCA4
RACMO22E
RCA4
REMO2009
WRF33
RCA4
RACMO22E
RCA4
REMO2009
Period
1970-2100
1951-2100
1970-2100
1951-2100
1970-2098
1951-2100
1971-2100
1970-2100
1951-2100
1970-2098
1951-2100
Institute
SMHI
CSC
SMHI
KNMI
SMHI
CSC
IPSL
SMHI
KNMI
SMHI
CSC
4