Historical dry spells in Malawi

Includes all the dry spells in Malawi from 2000 till 2021 per admin2. This historical dataset was produced as part of OCHA's Anticipatory Action pilot in Malawi. A dry spell is defined as at least 14 consecutive days with a cumulative rainfall of no more than 2 mm during the rainy season in an admin2 region. The dry spells are determined by using the CHIRPS dataset, which is raster data. This raster data was aggregated to admin2 by taking the mean value across all raster cells within an admin2. Description of columns:

• pcode: pcode of the admin2, retrieved from the COD administrative boundaries
• ADM2_EN: name of the admin2, retrieved from the COD administrative boundaries
• Season_name: the start year of the rainy season. not during a rainy season indicates dates that are outside the rainy season, according to the dates indicated in the rainy_seasons_detail_2000_2021_mean_back.csv. NA indicates the onset or cessation date of the rainy season is unknown.
• Dry_spell_first_date: the first day of the dry spell
• Dry_spell_last_date: the last day of the dry spell
• Dry_spell_duration: the number of days the dry spell lasted.
• Dry_spell_rainfall: total rainfall in millimeters during the dry spell. The cumulative rainfall during 14 consecutive days is computed on a rolling basis. This can cause the total rainfall to be more than 2mm, but during any 14 day period it is not more than 2mm.
• During_rainy_season: binary variable indicating if the 14th day of the dry spell is within the admin2’s rainy season, according to the dates indicated in the rainy_seasons_detail_2000_2021_mean_back.csv. NA indicates the onset or cessation date of the rainy season is unknown and it is therefore unknown whether the dry spell occurred during the rainy season.

​​Indicates the start and end of the rainy season in Malawi from 2000 till 2021 per admin2. This historical dataset was produced as part of OCHA's Anticipatory Action pilot in Malawi. The rainy season onset is defined as the first day of a period after 1 Nov with at least 40mm of rain over 10 days AND no 10 consecutive days with no more than 2mm of total rain in the following 30 days. The rainy cessation is the last day before a 15-day period after 15 March with 25mm or less of rain. The rainy seasons are determined using the CHIRPS dataset, which is raster data. This raster data was aggregated to admin2 by taking the mean value across all raster cells within an admin2. Description of columns:

• pcode: pcode of the admin2, retrieved from the COD administrative boundaries
• ADM2_EN: name of the admin2, retrieved from the COD administrative boundaries
• Season_approx: the start year of the rainy season.
• Onset_date: the start date of the rainy season according to the definition described above. NA indicates that the onset_date fell in a period that the dataset did not cover . This is the case for the season starting in 1999 since the months of October-December 1999 are not included in this 2000-2020 dataset.
• Onset_month: the month of the onset_date
• Cessation_date: the end date of the rainy season according to the definition described above. A indicates that the cessation_date fell in a period that the dataset did not cover.
• Cessation_month: the month of the cessation_date.
• Rainy_season_duration: the number of days between onset_date and cessation_date.
• Rainy_season_rainfall: the total rainfall in millimeters between onset_date and cessation_date.