Field

NCEP/NCAR 500mb height
mean daily NMC Reanalysis (1948)
X axis: whole world in 144 2.50° steps, first point at 0.00° E, last point at 357.50° E
Y axis: regular grid with 73 -2.50° steps, first point at 90.00° N, last point at 90.00° S
Z at 500.00 millibar air_pressure
1-daily data available from 01Jan1948 to 29Feb2021 ( 26778 times)
Variable hgt (mean Daily Geopotential height) in m
Full metadata.

Get grid points, average area or generate subset

Mask:	no mask mask17.txt ALA AMZ Antarctica Arctic CAM CAR CAS CEU CGI CNA EAF EAS ENA EQPacific MED NAS NAU NEB NEU NIndian NTPacific SAF SAH SAS SAU SEA SSA STPacific TIB WAF WAS WIndian WNA WSA   add a mask to the list
Latitude:	°N - °N
Longitude:	°E - °E
Boundaries:	halfway grid points interpolated
Make:	average max min set of grid points subset of the field
Demand at least:	% valid points in this region

Create a field with lower time resolution

New time scale:	annual (Jul-Jun) annual (Jan-Dec) biannual seasonal monthly 10-daily 5-daily
New variable:	mean sd sum sum above sum below number min time of min max time of max first time last time of 500mb height
Threshold:	no cut less than greater than m percentile normal 1971-2000
Minimum:	% valid data
First apply:	-day running mean
Missing data:	ignore, climatology, trend, persistence.

Create a field with lower spatial resolution

Average over blocks of longitude and latitude grid cells

Please consider downloading this field from the authoritative site.
If you really want to get it here, NCEP/NCAR 500mb height is available as a netcdf file (size 258.826 MB).