Observations for

Monsoon Asia Historical Temperature Monitoring

The Maproom explores historical daily temperature by calculating simple seasonal statistics.

Many options can be specified to produce yearly time series of a chosen seasonal diagnostic of the daily temperature data. The user can then choose to map the mean, standard deviation, probability of exceeding a chosen threshold, over years, coefficient of variation in percentage or percentile of historical distribution; 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.

Hot/Cold Day Definition: This threshold is used to define in Celsius degrees (non inclusive) the temperature under which a day is considered cold if the mean temperature is below it; or the temperature above which a days is considered hot if the mean temperature is above it; or the reference temperature to compute the growing/chilling degree days.

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.

Growing/Chilling Degree Days: Growing or chilling degree days are summations of positive/negative differences between the mean daily temperature and user-defined reference base temperature during the season. They are comparable to the more familiar cooling/heating degree day definitions utilized by energy-sector.
Number of Cold and Hot days: the number of cold or hot days during the season according to the user-defined threshold and according to the mean daily temperature.

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 coeffieient of variation (ratio of standard deviation to the mean) in percentage, and percentile of historical distribution (e.g., 0.1, 0.25, 0.5, 0.75, and 0.9).

Spatial Resolution: The analysis is performed and mapped at each grid point. Additionally it is possible to average the results of the analysis over the 0.25/0.5˚ grid points falling within administrative boundaries for the time series graph.

Dataset Documentation

Data: RIHN aphroTemp V1204R1 Monsoon Asia gridded daily temperature Data Set here.


Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.