Dew Point Temperature¶
In this section, MERRA-2 2-meter dew point temperature is compared to observations reported to the National Center for Environmental Information (NCEI – formerly National Climatic Data Center). Selected surface sites from the NCEI Integrated Surface Database (ISD) files are used for the hourly MERRA-2 comparisons. Global "Summary of the Day" (GSOD) files are used for the comparison to the daily mean MERRA-2 dew point temperature.
Hourly Dew Point Temperature
Scatter plot of the MERRA-2 hourly dew point temperature vs. the hourly station observations values from the selected NCEI ISD files for the years 2001 - 2019.
As with the daily average validation, the hourly validation shows good clustering along the 1:1 correlation line. The total number of hourly pairs is 220,615,418.
Daily Dew Point Temperature
Scatter plot of the re-gridded MERRA-2 daily dew point temperature vs. the daily station observations values from the NCEI GSOD files for every 3rd year from 1981 – 2014.
The color bar along the right side of the scatter plot provides a measure of the distribution of the NCEI, MERRA-2 dew point pairs in bins of 1°C. For example, in the scatter plot, the left column along the vertical color bar shows that each data point in dark blue represents the number of ground site/MERRA-2 data pairs within 10% (i.e. <=8,502.5) of the maximum number of data pairs within 1° C bins in the plot (i.e. 85,025). Additionally, from the right side of the vertical color bar it can be seen that all the points shown in dark blue contain 16.17% of the total number of ground site, MERRA-2 data pairs (8,543,089). The remaining 83.83% of the data pairs are concentrated along the 1:1 grey line.