Dry Bulb Temperature¶
In this section, MERRA-2 2-meter air 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 temperature.
Hourly¶
Hourly Dry Bulb Temperature
Scatter plot of the MERRA-2 hourly 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 229,482,314.
Daily Average¶
Daily Average Dry Bulb Temperature
Scatter plot of the re-gridded MERRA-2 daily average temperature vs. the daily station observations values from the NCEI GSOD files for every 3rd year from 1981 – 2014.
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. <= 8,608) of the maximum number of data pairs in 1°C bins in the plot (i.e. 86,080). From the right-hand column along the color bar it is seen that all of the points shown in dark blue contain 16.74% of the total number of ground site/MERRA-2 data pairs. Conversely, the darkest orange color represents regions with 68,864 to 77,472 matching temperature pairs (i.e. 80-90% of the maximum) and contain 8.03% of the total number of matching ground site/MERRA-2 data pairs. Thus, for the data shown in this figure, approximately 83% of matching temperature pairs (i.e. excluding the data represented by the dark blue color) are "tightly" grouped along the 1:1 correlation line.
Daily Maximum¶
Daily Maximum Dry Bulb Temperature
Scatter plot of the re-gridded MERRA-2 daily maximum temperature vs. the daily station observations values from the NCEI GSOD files for every 3rd year from 1981 – 2014.
Daily Minimum¶
Daily Minimum Dry Bulb Temperature
Scatter plot of the re-gridded MERRA-2 daily minimum temperature vs. the daily station observations values from the NCEI GSOD files for every 3rd year from 1981 – 2014.
