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.
Data: Reconstructed temperature data over land areas on a 0.05˚ x 0.05˚ lat/lon grid (about 5 km of resolution). Minimum and maximum temperature time series (1961 to 2019) were generated by combining quality-controlled station observations with downscaled reanalysis product.
Contact help@iri.columbia.edu with any technical questions or problems with this Map Room.