Tropopause maps



The tropopause maps are obtained by interpolating WRF fields onto the 2 PVU surface. Click here for a visualization of potential vorticity.

Tropopause maps and EPV tendency descriptions


Ertel potential vorticity (EPV) is obtained by interpolating potential temperature and three-dimensional winds from WRF eta levels to vertical pressure levels with a vertical spacing of 25 hPa. EPV diabatic tendency terms are calculated using diabatic tendency heating terms interpolated to pressure levels as above. The following describes these individual plots:

Tropopause theta or tropopause potential temperature is the potential temperature on the 2 PVU surface. Lower (cold) values correspond to relatively low tropopause heights while higher (warm) values correspond to relatively high tropopause heights. Locally cold areas are cyclones while locally warm areas are anticyclones.
Tropopause pressure is the pressure on the 2 PVU surface. In general, higher pressures correspond to lower tropopause heights and a greater chance of disturbed weather below.
Tropopause winds are the horizontal wind components on the 2 PVU surface.
Tropopause EPV diabatic tendencies are the changes in EPV from all diabatic heating tendencies. Positive values indicate regions where EPV is being created and negative values indicate regions where EPV is being destroyed. In general, if there are positive (negative) values over a tropopause cyclone, the cyclone is strengthening (weakening).
Tropopause EPV radiational tendencies are the changes in EPV from the radiational component of the diabatic heating tendency.
Tropopause EPV condensational tendencies are the changes in EPV from the condensational component of the diabatic heating tendency.
Tropopause EPV boundary layer and cumulus tendencies are the changes in EPV from both the planetary boundary layer and cumulus components of the diabatic heating tendency.



Tropopause potential temperature forecast verification


Tropopause theta forecast error is the difference between a WRF forecast and GFS analysis of tropopause potential temperature.
Tropopause theta instantaneous forecast error or daily error is the error of tropopause potential temperature for one time.
Tropopause theta long-term average forecast error is the average of the model error of tropopause potential temperature since the simulations began, on July 29, 2007.
Tropopause theta RMSE is the root mean square error of tropopause potential temperature. For example, the 24-hour RMS error takes the square root of the difference between the WRF 24-hour forecast and GFS analysis squared. Squaring ensures all values are necessarily positive.
Tropopause theta instantaneous RMSE or daily RMSE is the root mean square error of tropopause potential temperature for one time.
Tropopause theta long-term average RMSE is the average of the root mean square error of tropopause potential temperature since the simulations began, on July 29, 2007.



Other plot descriptions


3-hour accumulated precipitation is the total amount of precipitation that reaches the surface over a 3-hour period. If it is forecast to reach the ground in liquid form, then colors are plotted using a spectrum of colors ranging from blue (lightest amounts) to red (greatest amounts). If it is forecast to reach the ground in frozen form, then a gray colorscale is used to indicate it.
Column integrated cloud water and ice mixing ratio plots show where the model is predicting that clouds are most likely to be located. Relatively thick clouds are indicated with brigher white colors while relatitively thinner clouds are indicated by darker gray colors. The calculation is made by integrating cloud water and ice mixing ratios from the ground to the top of the model.
10-meter surface winds and SLP shows a plot of the horizontal wind magnitudes 10-meters above the ground in colors in units of meters per second, with windbarbs overlaid in knots. Sea level pressure (SLP) is also overlaid in contours.
Model soundings are Skew-T log-p plots following the location of lowest tropopause potential temperature value in the domain. A composite sounding shows the average sounding at the location of lowest tropopause potential temperature in the domain at analysis times only and when the minimum tropopause potential temperature is more than three standard deviations lower than the background.
Sea ice analyses show the approximate locations of sea ice determined by locating areas where sea surface temperatures are cold enough to be ice.