Lab 3 Key for Meteorologists

Part I

All are 7 points. (126 points in this section)

Locate the following features by placing the appropriate letters on the hard copies of the appropriate satellite image (click on Thumbnail to obtain large version for printing).

Points deducted for not doing analyses on full-sized maps (basically, if you didn't have enough patience to click on the satellite image and get the full-sized version to print, you didn't follow instructions...and, how you can see things like cloud lines on the thumbnails is beyond me

Image 1

i. A cloud shield. (S)

ii. Narrow cold frontal rainband (NCFR)

iii. A cloud street (St)

iv. Snow (Sn)

v. Stratus (Str)

vi. An area of texture (indicating either cumuliform tops or mutlilayered cloud decks) (T)

Image 2

vii. Stratocumulus (closed-cellular pattern) (SC)

viii.Cumulus (open-cellular pattern (CU)

ix.A Narrow Cold Frontal Rain Band (NCFR)

Image 3

x. Cirrostratus (Cs)

xi. A subsynoptic (large mesoscale) area of cumulonimbus anvils (CBA)

xii. Mountain Wave clouds (MW)

xiii. Higher clouds casting shadows on lower clouds (Shadow)

xiv. Incipient Frontal Wave Cyclone (IFW)

xv.Altostratus (As)

xv. Area where image suggests that upper tropospheric flow is NOT in phase with mid tropospheric flow (NIP)

xvi. An area of enhanced cumulus (EC)

xvii. Cirrus (Ci)


Part II

The visible, enhanced infrared and water vapor GOES-10 satellite images for approximately 1200 UTC 18 February 2003 are provided below. (174 points in this section)

Fronts

Fronts

 

1. On the blank map provided, sketch the upper tropospheric flow (streamlines) for the entire north Pacific (use Images B and D primarily for this). (30 points)

2. To the best of your ability, on a second blank map, do a frontal analysis for the north Pacific (use Images A, B and D for this). (30 points)

3. Note on the infrared image (conventional notation):

  1. Two long wave trough axes (black) (10 pts)
  2. Two long wave ridge axes (blue) (10 pts)
  3. A short wave trough axis. (purple) (10 pts)
  4. a sharp (green) and a broad (red) ridge axis (could be the same one/s you used in B. above). (10 pts)

4. Discuss why "sharp ridgelines" have little or no cirrus cloudiness past the ridgeline where as "broad ridgelines" often do. (16 pts)

The evaporation of cloudiness visible at a synoptic-scale on satellite imagery is related to synoptic-scale subsidence, often associated with migratory short-waves in the westerlies. The subsidence is linked to upper tropospheric convergence via mass continuity (Dine's Compensation). This convergence is strongest the shorter the wavelength of the disturbances in the upper troposphere (and the greater the curvature at the ridge axis). The maximum convergence is found generally at the inflection point east of a ridge axis, and the strength of that convergence (and associated mid-tropospheric subsidence) is directly related to the variation of curvature along the streamlines. For sharp ridge lines, the variation of curvature is great, and for broad ridgelines, the variation of curvature is small. Thus, the vertical motion necessary for cloud dissipation is found closer to the ridgeline the sharper the curvature of the contours.

 Part III. Satellite Oceanography (114 points in this section)

5. Get into this website: http://argo.colorado.edu/%7Erealtime/global-sst/

 

(a) Create a map of SST's for the West Coast of the U.S. for July 4, 2007. Use the Global High Resolution Sea Surface Temperature (GHRSST) data set. Use the following formatting options: Geographical Area....East Longitude Minimum 227; Maximum 245; Latitude Minimum 30; Maximum 45. Contours--Radio Buttons Checked: Show Contours; Annotate Contours; Contour Interval 2; Annotation Interval 5; Range of Data Values 8 to 25C; Tick Mark Interval 1. Print the map in color.(30 points)

 

July SST

 

(b) Indicate with the letter "U" the most dramatic upwelling plumes. (10 points)

 

(c) Indicate with a long arrow, the rough position of the California Current. (9 points)

 

6. Get into this website: http://www.cdc.noaa.gov/HistData/

 

(a) Create a map of sea-level pressure for the West Coast of the U.S. for July 4, 2007. Use the following options: start and end date are both 20070704; Variable is sea level pressure; Plot Type is mean; Map Domain is Custom; Latitude Range is 25 to 55; Longitude Range is 217 to 255; Color is Black/White; Shading Type is Contours Only; Contour Interval is 2, Range is 998 to 1024; Plot Size is 150%. Print the map. (30 points).

 

July Wind

 

(b) Indicate the sense of the winds with schematic short vectors along the California Coast. (10 points)

 

(c) Briefly discuss the relationship between (b) here and your answer in 5 (b). (15 points)

 

The afternoon winds suggested here would accelerate the surface flow in the California current out of geostrophic balance by increasing their speed. Since Coriolis acceleration is directly proportional to the currnt speed, an additional deflection to the right would occur in the surface current, creating flow away from the coast and, roughly, at 45 degrees to the wind. The blue arrows on the SST map indicte the net effect.The afternoon winds suggested here would accelerate the surface flow in the California current out of geostrophic balance by increasing their speed. Since Coriolis acceleration is directly proportional to the current speed, an additional deflection to the right would occur in the surface current, creating flow away from the coast and, roughly, at 45 degrees to the wind. The blue arrows on the SST map indicte the net effect.