3.3 Test 3 11-12 September 1979, Fellows Release (0700-1200 PDT)

3.3.1

General

Meteorology

The synoptic met eorol ogy during the test period was characterized

by a high pressure ridge at the 500 mb level along the west coast (Figure3.3.1). Temperatures aloft over Vandenberg and Oakland, as indicated by

the trend at 850 mb on Figure 2.2.1 were well above normal and near the

highest measured during the September intensive period. At the surface an

inverted pressure trough was located with its axis along the coast; fartherwest than typically. As a consequence, the onshore pressure gradients in

central California were weaker than usual. Skies in the San Joaquin Valley

were clear during the test. Visibilities throughout the valley generalllyranged between 10 and 15 miles. Surface temperatures were above the averagefor September. Maximum reported temperatures at Fresno and Bakersf ield were

102 °F and 104°F, respectively; or abo ut 10° above normal.

Transport Wi nds

As can be seen from the surface winds at Fellows, which are listed in

Table 3.3.1, the flow during the tracer release was typ ically from the east

and directed into the adjacent mountains at speeds on the order of 1-2 m/s.

The time cross section of the pibal winds measured at Taft (Figure 3.3.2)supports the general westerly transport at low levels during the release and

during the afternoon of the 11th. A short-lived shift to westerly winds

accompanied by an increase in wind speed was observed at 2100 POT but by thenext observation the winds had shifted back again to flow from the easterlyquadrants. Overall the winds i n the Taft-Fellows region were extremely lightand what little t ransport existed was directed westward, out of t he valley.

On a regional basis, the flow during the tracer release is shown bythe streaml ines in Figure 3.3.3. Although a generally cyclonic flow patternwas occurring in a major porti on of the valley, the flow in the southwestregion rema ined unaf fect ed. In fact, only slight air movement was observedthroughout the southern San Joaqu in Valley. Regional flows remained light

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