The Maproom explores historical daily precipitation by calculating simple seasonal statistics.
Many options can be specified to produce yearly time series of a chosen seasonal diagnostic of the daily precipitation data. The user can then choose to map the mean, standard deviation or probability of exceeding a chosen threshold, over years; clicking on the map will then produce a local yearly time series of the chosen diagnostic.
Years and Season:
Specify the range of years over which to perform the analysis, and choose the start
and end dates of the season over which the diagnostics are to be performed.
Seasonal Data Coverage:
A minimum fraction of non-missing days per season can be required in order for the
seasonal diagnostic to be defined at that station — if this minimum threshold is not
met, then the seasonal diagnostic is assigned a missing value at that station, for
that season and year.
Wet/Dry Day/Spell Definitions:
These define the amount in millimeters (non inclusive) above which a day is considered
to be a wet day (as opposed to dry), and the minimum number (inclusive) of consecutive
wet (dry) days to define a wet (dry) spell.
Seasonal daily statistics: Choose the seasonal diagnostic quantity (i.e., the statistic of the daily data)
to be computed for each season, from the following choices.
Total Rainfall: total cumulative precipitation (in mm) falling over the season.
Number of Wet Days: the number of wet days (as defined above) during the season.
Rainfall Intensity:
the average daily precipitation over the season considering only wet days.
Number of Wet (Dry) Spells:
the number of wet (dry) spells during the season according to the definitions in the
Options section. For example, if a wet spell is defined as 5 contiguous wet days,
10 contiguous wet days are counted as 1 wet spell. Note that a spell, according to
the definitions above, that is overlapping the start or end of the season will be
counted only if the part of the spell that falls within the season reaches the minimal
length of consecutive days.
Percentage of Data Available: the percentage of days with non missing values within the season.
Yearly seasonal statistics: a choice of yearly statistics over the chosen season of the selected range of years
to produce the map among: the mean, the standard deviation, the probability of exceeding
a user specified threshold, the coefficient of variation and the value of a user specified
percentile.
Data: CCROM-ASEAN network of meteorological stations here.
Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.