NARCCAP Data Tables

NARCCAP data is organized into groups based on its spatial and temporal structure: 2-D vs 3-D, daily vs 3-hourly, etc. The groups are listed in the table below:

Notes:

The "screen height" or "reference height" is 1.5-2 m above the surface.

Quantities that can be used for storage terms in budgets are instantaneous values. Quantities that are fluxes in budgets are average values for the 3-hr period prior to the reporting time.

3-hourly values (Tables 2, 3, & 5) are reported at 03 UTC, 06 UTC, … 24 UTC.

The "day" for daily min/max values (Table 1) is from 06 UTC - 06 UTC, with the date stamp referring to the beginning time.

Table 1

Minimum and maximum daily temperatures [tasmax, tasmin] are recorded from instantaneous screen height temperatures sampled every time step during the course of the day.

Table 2

Winds [uas, vas] are true west-east and south-north winds, i.e., rotated from the model's grid to the earth's longitudinal and latitudinal directions.

Surface air temperature [tas] and specific humidity [huss] are recorded from screen height values, 2 meters above the surface.

Surface winds [uas, vas] are recorded from "anemometer level" values, 10 meters above the surface.

Units for precipitation [pr] and surface pressure [ps] are MKS, following CF standards.

Table 3

Snow depth [snd] is snow-water equivalent and is the average depth over the entire grid box, even if the model allows snow to cover a fraction of the grid box.

Table 4

Land-cover type [landtyp] is a vegetation index linked to a table supplying land-cover descriptions.

Table 5

3-D fields are provided very 25 hPa from 1050 hPa to 25 hPa.

Note that according to the CF conventions, ice and liquid cloud water [cli, clw] are each reported as a ratio: (cloud-water mass)/(mass of gas+condensed constituents), i.e., more like specific humidity than mixing ratio.