NSF C-130 Mission Summary Report (EPIC)

RF14 - C-130 95 W Transect

Mission Summary - This mission represented the sixth 95 W transect.  The overall
weather conditions featured a highly suppressed ITCZ, as during the previous
95 W transect mission of 25 September.  Unlike on 25 September, however, there
was even a lack of cirrus clouds at the ITCZ.  The only precipitation encountered
during the flight was a minute or two of light rain near 5 N. South of the ITCZ,
the ABL was characterized by typical (at least for EPIC 2001) thermodynamic
properties.  The southerly winds over the cold tongue and SST front were relatively
strong.  It was relatively moist right above the ABL, and the trade-wind
inversion seemed less prominent than on the previous surveys.  For the first
time, there was a layer of overcast (1.8 km level) above the ABL in the
vicinity of the cold tongue.  The dropsondes south of 7 N indicated very dry
conditions (some regions RH << 10%) above 3 km/700 mb.  The deployment of the ocean
probes was successful with signal returned by 13/13 BT's, 4/6 CTD's, and
5/5 CP's.  All 13 dropsondes seemed to work properly, though there seems to be
some problems in the conversion of the raw text data to netCDF format.

Flight notes

1431	Take Off
1433	Ascending, CLR OVHD, strong E winds (80 @ 13 m/s) from 1-2.2 km
1445	Lat 15, whitecaps
1526	Lat 12.3, 100', SST 29.3, TA 29.1, wind 123 @ 2-3 m/s, thetae 358
	q 19, rippled sea with swell from the south, fair-weather Cu
1530	Spotted 12 N buoy, SABL out
1532	Begin ascent, clouds from 400 to 500 m, CLR OVHD
1541	Lat 11.4, 5000', wind 112 @ 12 m/s, thetae 339, q 11, well-defined
	transition layer in O3 in previous ascent, but not apparent in
	thermo. data, hazy almost brownish towards horizon, CLR OVHD,
	few-SCT Sc and BL Cu below
1549	Lat 11.0, begin descent, SCT Cu and Sc below
1556	Lat 10.6, 100', SST 29.8, TA 29.3, Wind 130 @ 2, thetae 354, q 18
1607	Lat 10.0, began ascent, cloud base 350-400 m, tops 550-700 m,
	irregular dist. of cloud heights and coverage, considerable
	wind shear w/light chop,small cloud deck near 1.4 km, CLR above
1617	Lat 9.3, 5000', wind 98 @ 13 m/s, thetae 346, q 14, SCT Cu & Sc
1623	Lat 8.6, began descent in CLR air, linear streaks on ocean sfc.,
	vertical profiles in kinematic and thermo. properties all look
	the same so far
1629	Marine mammals spotted near surface, light chop below 70 m
1630	Lat 8.5, began 100', SST 28.8, TA 28.3, wind 160 @ 2-3, thetae 352,
	q 17, relatively light turbulence, SCT small Cu OVHD, CLR above BL
1639	8 N buoy spotted
1640	Lat 8 N, began ascent, BL clouds between 300 and 500 m
1643	BT (good), small patch of Ac/As above
1646	CP (good)
1647	Lat 7.6, 5000', CTD (bad), wind 70 @ 10, thetae 344, q 13, CLR above
1654	Lat 7.2, start descent, BT (good), unusual lack of BL and upper clouds
	for the region, very little turbulence on descent
1659	Lat 6.9, start of 100', SST 28.3, TA 28.1, wind 160 @ 3 m/s, thetae 350,
	q 17, rippled sea, SCT BL Sc
1708	BT (good), more clouds in multiple layers below 800 m and near 1 km
1711	Lat 6.2, level at 5000', CP (good), clipping some cloud tops, wind
	90 @ 7-8, thetae 341, q 12
1713	CTD (good)
1719	Lat 5.7, start descent, BT (good), cloud tops 1400 m, in thick cloud
	until about 1 km, lower cloud deck between 500 and 300 m, much
	grayer than earlier near surface
1725	Lat 5.4, 100', SST 28.0, TA 26.8, wind 210 @ 3 m/s, thetae 350, q 17
1727	Lat 5.3, into light precip., winds picking up 195 @ 5-6 m/s, R/V 
	Brown sighted
1729	Out of precip
1730	Past Brown, into light precip again
1731	Lat 5.0, began ascent
1735	BT (good), cloud top near 900 m
1736	A few more clouds near 1400 m, CLR above
1737	CP (good)
1738	Lat 4.6, at 5000', wind 65 @ 9 m/s, thetae 342, q 13
1739	CTD (good)
1742	Lat 4.4, clipping tops of BL clouds at 5000'
1744	Lat 4.2, began descent, BT (good)
1750	Lat 3.9, start of 100', more turb., whitecaps, SST 27.3, TA 26.0,
	wind 170 @ 9, thetae 342, q 15, thick OVC, some irregularity in
	cloud base height, noticeable swell
1756	Lat 3.6, spotted buoy
1757	Lat 3.6, began ascent, cloud bases 250-300 m
1800	BT (good)
1803	Lat 3.3, start of 5000', CP (good), uniform cloud tops near 1400 m
1804	Lat 3.2, 5000', wind 48 @ 10 m/s, thetae 343, q 13
1805	Lat 3.15, CTD (good), uniform undercast, CLR above
1811	Lat 2.8, begin descent, BT (good), cloud tops near 1500 m, sharp
	windshift near cloud top, cloud bases 300-350 m, undulations/rolls
	in cloud base heights
1817	Lat 2.45, start of 100', whitecaps, SST 26.5, TA 23.8, thetae 335,
	q 14, wind 170 10-11 m/s, more turb. than previous 100' run but
	still mostly light, getting thin spots in OVC
1825	Lat 2.1, start ascent, cloud base about 450 m, tops 800-900 m, CLR OVHD
1828	BT (good)
1831	Lat 1.7, start of 5000', CP (good), a few patches of very thin clouds
	above, wind 65 @ 2, thetae 342, q 13
1833	CTD (bad), occasionally hitting cloud tops
1837	Lat 1.4, replacement BT (good)
1840	Lat 1.2, began descent, BT (good), cloud top near 1400 m, base near 900 m
	lower deck between 200-500 m, starting to get better BL and TWI signature
	in static stability
1846	Lat 0.9, near start of N-S 100', SST 22.5, TA 21.7, wind 164 @ 9,
	some whitecaps, thetae 330, q 13
1854	Lat 0.5, start of 100' E-W leg, SST 20.1, wind 155 @ 8 m/s, uniform
	 OVC, SABL shows most clouds between 1100 and 1300 m (not picking up
	low clouds)
1859	Lat 0.5, start of ascent, still two cloud decks with clear but hazy
	air between
1901	Lat 0.4, BT (good), cloud top near 700 m, higher deck OVHD w/ tops
	near 1500 m
1906	Lat 0.1, CTD (good)
1908	Lat 0.0, 5000', near cloud tops, wind 75 @ 10, thetae 341, q 13
	began entering wispy clouds extending maybe 1000' above (based on
	SABL)
1912	Lat -0.2, start descent, BT (good), clearing OVHD, unimpressive
	trade-wind inversion, speed max at 500 m (150 @ 15 m/s)
1919	Lat -0.6, SST 18.2, TA 20.5, wind 155 @ 6, thetae 329, q 13,
	pod of pilot whales or dolphins, SABL indicates OVC at 1.7-1.8 km
	level but not distinct low-level stratus
1926	Lat -1.0, start of 100' E-W leg, SST 18.5
1946	Lat 0.0 (on ascent for inbound ferry), 1st GPS sonde good
2028	Lat 3.3, flight level wind 280 @ 3 m/s
2041	Lat 4.4, SABL shows very complicated BL cloud organization
2052	Soundings between 3-5 N show very dry layer near 15,000'
2155	Lat 10, convection beginning to fire up a bit in vicinity