If you're a newcomer to meteorology, you'll quickly discover that not all weather data is 100% accurate. Errors can get into raw weather data either through transmission problems, communications interference, human error, or simply the observer hitting the wrong key when typing up the report. These can either be unnoticable or may corrupt an analysis. Fortunately, Digital Atmosphere provides a tool to help fix the problem.
To perform quality control, simply drag the mouse over the location where erroneous data is suspected. A box will appear, as shown below:
When you select File > Quality Control or press the QC speed button, the quality control panel will appear, as seen below:
You may then edit the values shown and correct any entries that look suspicious. Always use a value of -9999 to indicate missing data.
Note that the data shown is dependent on what the active level is (as is shown on the Time Toolbar). If the active level is a non-surface level, Quality Control will only display upper-air data. If the active level is a surface level, Quality Control will display only surface data.
The options you have are:
Note that QC displays all data within the bounding box (even if it's filtered out on the map), so you may need to press "Accept entry" numerous times until you find the station you want. One way of avoiding this problem is to make the initial QC box as small as possible so that you get only the station you want.
Since QC changes the formatted binary data files, you will lose your changes if you re-import the original data.