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.
The KSPM was produced by the International Research Institute for Climate and Society (IRI) for review by the United States Agency for International Development and partners on the BAWP and do not necessarily reflect the views of USAID.
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 statistcis: 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 and the probability of
exceeding a user specified threshold.
Resolution: a choice to map the yearly seasonal statistics of either the PAGASA meteorological
stations or the 0.25˚ APHRODITE grid boxes.
Mask:
In the case of APHRODITE, the dataset includes a record of the number of station data
observations present for each gridbox on each day of the dataset. Gridbox-days without
at least one observation can be masked prior to any calculations (masking so called
interpolated values).
Data: daily stations precipitation from PAGASA: Philippine Atmospheric, Geophysical and Astronomical Services Administration.
Data: RIHN aphrodite V1101 Monsoon Asia gridded daily precipitation here.
Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.