\ Subtropical Highs

Subtropical High Example Results:


Page Last modified: 20 January 2009
This material was supported in part by the National Science Foundation under Grant No. 96-15316. Additional funding from UCDavis Temporary Hatch account RDG8.

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  1. Invited Talk at IUGG 2007 in Perugia Italy on 5 July 07

    Pdf of the talk This file is 3.1 MB. My presentation was titled: "Observational Study of Subtropical Highs"
    It includes monthly & daily observational results from all 5 highs. It includes simple conceptual models and expanded forcing information.

  2. Seminar at Pasadena on 5 November 04

    Powerpoint presentation of the talk This is a LARGE file! 7.8 MB. My presentation was titled: "Pacific Subtropical Highs: Features Interacting with Midlatitude and Tropical Forcing"
    It includes monthly & daily observational results from SP and NP high. It includes simple conceptual models and expanded forcing information.

  3. Seminar at UCD on 5 May 04

    Powerpoint presentation of the talk This is a LARGE file! 7.9 MB. My presentation was titled: "On Remote Weather Associated with the Subtropical Highs of Pacific Sea Level Pressure". It includes monthly results from SP and NP high. It includes daily data results only for the SP high.

  4. Some figures related to an FY01 NSF Proposal

    • Color Figure in the Proposal:
      • Figure 1. 1-point correlations using 6 different points (marked with a circle) surrounding the climatological NP high location (marked by an H).
        Shaded areas have correlation exceeding a 95% significance test. The contours are drawn for correlations having magnitude of 0.3 or higher with 0.1 interval.
        Note: the color scale on the 1-pt correlation figure differs from the color scale used below. Here a "negative" (color reversed) image was prepared from the black-background figures below. Consequently, lighter shading (cyan) here is red below and dark brown here is blue below.

    • Annotated reference table of selected observational papers. This acrobat reader file (.pdf) is intended to show similarities in methods and gaps in prior studies.

  5. Southern Hemisphere Subtropical High experiments

    • Comparison of OLR and P composite differences using strong SP highs minus weak SP high months.

    • These SH figures were produced by student Sheri Immel using NCEP/NCAR reanalysis monthly SLP and OLR data 1979-1997 (19 years) {2.5x2.5 lat/lon grid. Daily data for SLP, daily averaged data for interpolated outgoing longwave radiation (OLR)}
      • SLP climatology Box & whisker plot where:
        • Each box encloses the middle 2 quartiles
        • Heavy bar is the mean
        • the lighter bar is the median.
        • Plus symbols are the extremes while the lighter bars indicate 2 standard deviations from the mean in a given direction.
    • Composite averages using the summer (JFM) months. The 12 months with highest SLP central pressure and the 8 months with lowest SLP central pressure.
      Criterion: strong events exceed the mean SLP for the season by 1 standard deviation. Similarly for weak SP high months.

  6. 13th Conference on Atmospheric and Oceanic Fluid Dynamics - Breckenridge, Colorado, June 2001


    Selected items from the poster (May 2001).
    • Fig. showing median peak monthly mean SLP for the NP and SP highs by calendar month.
    • Fig. showing SLP and P composites of strong NP highs during May-September. Significant areas shaded. Anomaly data used.
    • Fig. showing SLP and P composites of strong SP highs during October-February. Significant areas shaded. Note: the SP high has similar appearance and strength during these months but it looks very different in March. Anomaly data used.
    • Fig. showing NP high 1-pt correlations of the 2-D P field for selected SLP points to the sides. Total data are used. THE FIGURE IS THE SAME AS IN THE PREPRINT VOLUME.
    • Fig. showing SP high 1-pt correlations of the 2-D P field for selected SLP points to the sides. Anomaly data are used.
    • Fig. showing SLP composites of strong highs but with a larger domain. Upper is for summer NH highs lower chart is for summer SP highs. NP highs associated with some SH changes that appear to be significant, but SP highs are not associated with NH changes. Anomaly data used.
    • Part of the poster presentation (text only) in powerpoint (.ppt) format. Portions of the figures used are in separate links above.

    Preprint volume (material dated from January 2001)

    • Extended abstract using color figures (1.2 Mb size)
    • Extended abstract using black and white figures (0.5 Mb size)
    • Enlarged version of Figure 1. as in the preprint volume making a comparison of OLR and P composite differences using strong SP highs minus weak SP highs.

    • Enlarged version of Figure 2. as used in the preprint volume showing 1-point correlations using 6 different points (marked with a circle) surrounding the climatological NP high location (marked by an H).
      Shaded areas have correlation exceeding a 95% significance test. Contour interval is 0.1 correlations that exceed 0.3 in magnitude.
      Note: the color scale on the 1-pt correlation figure differs from the color scale used below. Here a "negative" (color reversed) image was prepared from the black-background figures below. Consequently, lighter shading (cyan) here is red below and dark brown here is blue below.

  7. 6th Southern Hemisphere Meteorology Conference Presentation - Santiago, Chile April, 2000 (selected figures only)

  8. Northern Hemisphere Subtropical High experiments

    1. Average fields for the 45 months of June, July, and August
    2. "1-point" Correlations:
      1-point correlations that compare a SLP property against a two-dimensional precipitation field.
      These correlations use the following plotting convention: contours are at 0.1 interval for correlations whose magnitude meets or exceeds 0.3. Also, shaded areas denote regions where the correlation passes a 95% significance test. Blue indicates a negative correlation; red a positive.
        For 8 grid points that surround the center of the summer subtropical high. A 9-point average is used to define the "grid point" value. The images move clockwise around the anticyclone center starting in the NW quadrant.
      1. NW of high
      2. N of high
      3. NE of high
      4. E of high
      5. SE of high
      6. S of high
      7. SW of high
      8. W of high
    3. Composites:
        Stong minus weak composites of...
      • SLP
      • Precipitation
        Red means more precipitation for the stronger highs; blue means less precipitation for the stronger highs.
      • Mixed results: (examples)
        1. slight evidence supporting the "current view" (unlike the correlations) is perhaps the most notable. Stronger high with more precip over Mexico and northern Central America, though there is less over the Caribbean and the ICZ is shifted away (dipole pattern) so there is less precip over much of the area to the southeast of the high, as well.
        2. Dipole pattern appears elsewhere, too. in tropical west Pacific implies shift of precipitation away from the high when high is stronger -- similar to the result found in the South Pacific subtropical high.
        3. The postulated storm track shift (seen strongly in 1-pt correlations) is not so obvious here.
        4. Need to reexamine the months chosen for these composites. Perhaps more definitive examples can be selected from a longer record. Greater sample size, isolating competing effects, etc.

  9. Miscellaneous

    • .gif movie" monthly mean SLP The blue contour is the 1016mb and the red/pink contours are 1020mb and higher with a 1mb increment. Green indicates annual average. Notice the sloshing back and forth of mass between the Northern and Southern Hemispheres. file produced by Ms. Sheri Immel

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