GlobalCDA is a DFG-funded research unit that aims at improving our understanding of the global freshwater system by combining hydrological modelling with remote sensing data. Since June 2018 nine project partners from Germany, Luxembourg and UK are working on developing a calibration and data assimilation framework, on refining the underlying hydrological model and on generating accurate remote sensing data sets. DGFI-TUM contributes in the projects WALESA and ARISAS by providing water level time series for inland water bodies based on satellite altimetry.
For more information on GlobalCDA please visit http://globalcda.de/.
Data download can be performed with the Python 2.7 script below. Please copy the script to your computer and specify your personal login credentials in fields 'username' and 'password'. The data will be downloaded to a local directory that is given in 'download_path' (make sure that this directory exists on your computer). If no further arguments are defined, all available DAHITI-targets will be downloaded. To select a certain region of interest or a particular water body please define one of the following arguments:
| 'basin_id': | Indicate here the BASIN_ID from WaterGAP to download time series for all targets with reference points inside the basin. |
| 'poly_id': | This argument may be used to find global lakes and reservoirs as defined by POLY_ID in WaterGAP. |
| 'arc_id': | Search for all water bodies whose DAHITI polygon overlaps the particular WaterGAP grid cell. |
For every water body a text file consisting of the water level time series plus some header information is downloaded. The header includes the DAHITI-ID and target name, the location of the reference point, statistics about the time series and the WaterGAP-IDs. The mapping between DAHITI-targets and WaterGAP-IDs is done as follows: For every DAHITI-target 'basin_id' and 'poly_id' are determined by the target's reference point, i.e. both consist of one single value. In contrast, 'arc_id' is a list of all grid cells containing the DAHITI-polygon. This polygon is usually larger than the corresponding one used in WaterGAP.
Please note that your account must be added to the 'GlobalCDA' group to access parameters such as 'arc_id', 'poly_id' and 'basin_id'. In case the download is not working, please contact us. Please also note that DAHITI-targets with a surface area time series but no water level time series will appear with the remark 'Permission denied'.
| GlobalCDA-Downloader (v1.1) |
Water level time series for DAHITI-ID: 315 (Amazon, River)
# DAHITI-ID : 315
# Target name : Amazon, River
# Location : None
# Continent : South America
# Country : br
# Longitude : -59.0727
# Latitude : -3.2467
# Points : 377
# Software : 6.0
# Download : 2019-06-26 15:59:04
# Last-Update : 2019-06-22 06:15:46
# Arc-Id : 55244
# Poly-Id : None
# Basin-Id : 9232
# ----------------------------------------
# column 1 : date [yyyy-mm-dd]
# column 2 : normal heights w.r.t. geoid model [m]
# column 3 : error [m] (Kalman Filter, formal errors)
# column 4 : dataset (OP:operational, RT:real-time, CB:operational+real-time)
# ----------------------------------------
2008-07-17 18.583 0.0258 OP
2008-07-27 17.799 0.0461 OP
2008-08-06 17.802 0.0102 OP
2008-08-16 16.693 0.0793 OP
2008-08-26 15.981 0.043 OP
2008-09-05 14.948 0.0081 OP
2008-09-15 13.564 0.0055 OP
2008-09-25 11.903 0.0012 OP
2008-10-05 11.436 0.0102 OP
2008-10-15 8.629 0.0321 OP
2008-10-25 6.823 0.1833 OP
2008-11-04 10.782 0.1102 OP
2008-11-13 10.595 0.0325 OP
2008-11-23 8.827 0.1063 OP
2008-12-03 11.637 0.0158 OP
2008-12-13 12.228 0.0015 OP
2008-12-23 12.020 0.0736 OP
...