While shading red, he stated, "So, here you have your vorticity max at the base of this trough, so that means that your PVA is going to be right here, just east, northeast of that trough base." Similarly, as he shaded blue, he said, "And your negative vorticity
advection is going to be just west of that trough base as you approach that subgeostrophic flow down there and as you approach that vort max.
investigating fall precipitation in the northern coast of Iran, showed that a high-pressure center on the west of the Caspian Sea and negative vorticity on the sea in lower levels of the atmosphere combined with strong currents and prevailing in the north-south direction are the main factors causing heavy and extreme fall precipitation in all the synoptic patterns of the Caspian .
In the northern hemisphere, a positive vorticity indicates a cyclonic motion and a negative vorticity demonstrates an anticyclonic motion.
Figures 2(a) and 2(b) further show, right upstream from the cylinder, a central structure under the free-surface level, as characterized by negative vorticity
(Figure 2(a)) and remarkable depth (Figure 2(b)).
It should be noted that our focus was to analyze vortex behavior in three-dimensions, so both positive and negative vorticity were important for analysis.
In the baby-rain-cells that did not form supercells, clearly, both positive and negative vorticity existed.
However, the negative vortices would be formed on the leeward side of the wavy flow structure (positive vorticity denotes a counterclockwise rotation and negative vorticity, a clockwise rotation).
(3) For the time-averaged longitudinal vorticity, the coupling magnitude of positive and negative vorticity differs in the classical and pulsating JICF.
A broad area of positive vorticity advection (PVA) was found ahead of the moving trough over the period, entering extreme western New York at 0000 UTC 12 January 2004, and subsequently replaced by negative vorticity
advection (NVA) by 1200 UTC.
In addition, the simulation produces only low levels of positive and negative vorticity
. The 2RAD forecast (Figures 12(d)12(f)) used data from only the KTLX and KOKC radars, and although it captured more of the low-level wind structure than the KOKC experiment, their volume scans still did not observe the top portion of the storm.
Downward motion of air occurs in positive vorticity area at 500 hPa level (approximately 5.5 km height) and oppositely upward motion in negative vorticity area.
At 0900 LST October 27, Gangneung city was in negative vorticity area at the 500 hPa level, which caused upward motion of air with a magnitude of -4 x [10.sup.-5] [sec.sup.-1] from the ground surface toward the 500 hPa height.