Consecutive Dry Days (CDD).

About the data.

 

Data: CHIRPS and IMERG

Reference:

  1. CHIRPS https://chc.ucsb.edu/data/chirps

  2. IMERG https://gpm.nasa.gov/data/imerg

Source:

  1. CHIRPS https://data.chc.ucsb.edu/products/CHIRPS-2.0/global_daily/

  2. IMERG https://gpm1.gesdisc.eosdis.nasa.gov/data/GPM_L3/GPM_3IMERGDF.06/

Spatial resolution:

  1. CHIRPS: 0.05 deg ~ 5.6 km at equator.

  2. IMERG: 0.1 deg ~ 11.1 km at equator

Temporal resolution:

  1. CHIRPS: 1 Jan 1981 - 31 May 2020, daily

  2. IMERG: 1 Jun 2000 - 7 Apr 2021, daily

Coverage:

  1. CHIRPS: 50N-50S, 180W-180E

  2. IMERG: 90N-90S, 180W-180E

Method:

  • The longest period of consecutive days with no or less than 1 mm precipitation. 1 mm is common threshold of precipitation total for each day which can be categorized as rainy day and use widely by meteorological bureau..

  • Let RRij be the daily precipitation amount per day i during time period j. Count the largest number of consecutive days where: RRij <1 mm

Script:

Code to calculate CDD available at: https://gist.github.com/bennyistanto/40222d0a00d7e67eda8ec30900732d7e

Unit:

Number of days.

Format:

GeoTIFF (*.tif)

Projection:

EPSG:4326

License.

 

For CHIRPS-based product, the license is WTFPL.

Symbology.

 

ArcGIS: CDD.lyr

QGIS: CDD.qml and CDD.qlr

GeoServer: CDD.sld

Download.

 
CDD_1mm.png

CDD, rainy day ≥1mm.

CHIRPS: https://on.istan.to/39xnkOW

IMERG: https://on.istan.to/3g7eav9

 
CDD_10mm.png

CDD, rainy day ≥10mm.

CHIRPS: https://on.istan.to/3317zi5

IMERG: https://on.istan.to/30Y991u

 
CDD_2.5mm.png

CDD, rainy day ≥2.5mm.

CHIRPS: https://on.istan.to/2P2016v

IMERG: https://on.istan.to/3fatoy2

 
CDD_20mm.png

CDD, rainy day ≥20mm.

CHIRPS: https://on.istan.to/30T0D3T

IMERG: https://on.istan.to/3f8CYSf

 
CDD_5mm.png

CDD, rainy day ≥5mm.

CHIRPS: https://on.istan.to/2BCqEvH

IMERG: https://on.istan.to/3f7yD1A

 
 
Next

Consecutive Wet Days