Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev.,...
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Transcript of Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev.,...
![Page 1: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/1.jpg)
![Page 2: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/2.jpg)
Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639.
Shapiro (1984)
![Page 3: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/3.jpg)
BAO tower
WNW downslope
flow
Temperatures (°C)winds (barb = 10 kts)
The passage of a strong cold front in eastern Colorado
We will be interested in the structure of this front as it passes the
Boulder Atmospheric Observatory tower
![Page 4: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/4.jpg)
The Boulder Atmospheric Observatory Tower located in Erie, Colorado near I-25
![Page 5: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/5.jpg)
Cross section of the cold front that passed the BAO tower on 24 March 1982
Based on a rawinsonde at Denver, a radiometer temperature profile, a lidar wind profile and surface data
![Page 6: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/6.jpg)
Potential temperature (K, solid) and front normal wind component (m/s, dashed)
Two minutes!!!
300 meters
superadiabaticlapse rate
![Page 7: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/7.jpg)
Vertical motion (m/s) measured by sonic anemometers on the tower
Frontal boundaries denoted by solid lines
![Page 8: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/8.jpg)
zy
w
xy
u
yy
v
ydt
d
Miller 2-D frontogenesis function (neglecting diabatic processes and turbulence)
Change in potentialtemperature gradient
following parcel
Confluenceacting ongradient
Shearacting ongradient
Tilting of verticalgradient
Can’t evaluate this -so assume negligiblebased on surface data
Do the flow fields suggest that frontal contraction was occurring at the time the front passed the tower?
![Page 9: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/9.jpg)
Miller 2-D frontogenesis function (neglecting diabatic processes and turbulence)
Change in potentialtemperature gradient
following parcel
Confluenceacting ongradient
Shearacting ongradient
Tilting of verticalgradient
confluence term
zy
w
xy
u
yy
v
ydt
d
![Page 10: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/10.jpg)
Miller 2-D frontogenesis function (neglecting diabatic processes and turbulence)
Change in potentialtemperature gradient
following parcel
Confluenceacting ongradient
Shearacting ongradient
Tilting of verticalgradient
Tilting term
zy
w
xy
u
yy
v
ydt
d
![Page 11: Shapiro, M. A., 1984: Meteorological tower measurements of a surface cold front. Mon. Wea. Rev., 112, 1634-1639. Shapiro (1984)](https://reader036.fdocuments.net/reader036/viewer/2022062409/56649ee55503460f94bf57cd/html5/thumbnails/11.jpg)
Miller 2-D frontogenesis function (neglecting diabatic processes and turbulence)
Change in potentialtemperature gradient
following parcel
Confluenceacting ongradient
Shearacting ongradient
Tilting of verticalgradient
Total frontogenesis
0
0
ydt
d
ydt
d
Frontolytical
Frontogenetical
zy
w
xy
u
yy
v
ydt
d