NSF C-130 Mission Summary Report (EPIC)

RF06
95W Mission

Summary - First combined ocean probe/atmospheric profiling mission along 95W.
There were some differences in the atmospheric conditions relative to that
of the 95 W mission of 7 September.  In particular, while it was relatively
moist above the ABL on both days, there was weaker NE flow above the ABL
south of the ITCZ on the 14th than on the 7th.  On the 14th, the SST front was
in the southern extent of its expected range (the SST was 25 at 0.8 N and
19 C at 1.0 S).  The atmospheric conditions across the SST front featured
a change from fair weather Cu and Sc on the north side to stratus on the
south side.  The cloud coverage was only somewhat less on the south side.
Very low cloud bases (sea fog?) and perhaps some very limited patches of
light drizzle were observed south of the SST front.  Continuous weak
stratification was noted in the ABL south of the SST front; a well-defined
mixed layer was noted north of the front.  The capping inversion layer
south of the front was surprisingly weak, based on the flight-level data
from the low-level profiles.  Somewhat disappointing performance for the
ocean probes.  Success rates: BT's - 6/12; CTD's - 5/5; CP's - 3/6.  The
average success rate of about 70% for the new probes compares unfavorably
with the success rate (after 1 mission) of greater than 90% from the P-3.
The success rate of 50% for the BT's is much lower than expected, and
for unknown reasons.

Flight Notes

1333	Take Off

1354	Lat. 14.5, SCT towering Cu in vicinity, considerable Ci,
	Wind 50 @ 4 m/s
 
1400	Lat. 14.1, Large mature Cb cluster to the E

1419	Into Cloud, Ship off east side

1425	Lat. 12.5, Wind 340 @ 2.5 m/s

1427	Approaching start point, CLR, rippled sea

1429	Descent sounding near 12 N, ABL about 1000 m deep, q about 12 g/kg
	above ABL

1431	Spotted 12 N TAO buoy, SST about 29.3

1432	Beginning ascent to 5000' at 12 N, shallow Cu to the south

1435	Lat 11.8, SCT-BKN fair-weather Cu

1436	Drier above ABL on ascent (about 2 g/kg less)

1440	Lat 11.6, at 5000' above all low-level clouds

1448	Lat 11.0, 5000', Wind 90 @ 2.6 m/s, q about 11 g/kg

1458	Lat 10.4, 100', Wind 160 @ 6 m/s, SST - TA about 2 deg.,
	LGT Turbulence

1507	Flew past R/V Ron Brown at 100', LGT Turb.

1508	Beginning ascent to 5000', SCT-BKN Ci OVHD, Considerable
	and multiple layer cloud decks

1511	Lat 11.5, Thermodynamic profiles similar to previous, Wind
	90 @ 5 m/s at 1300 m, max. wind at about 1000 m

1516	Lat 9.3, Ci at 6-6.5 km level based on SABL, other clouds at
	4-4.5 km

1521	Lat 9.0, a few lines of shallow fair-weather Cu below

1524	Lat 8.3, beginning descent to 100', considerable light
	precip in area based on nose radar and visual obs., some
	thick clouds with bases at 1.8 km.

1530	Lat 8.5, beginning 100' leg, SST - TA about 2.5, SST 29,
	LGT Turb, a bit drier above the ABL than last profile

1532	Lat 8.36, in light precip, winds 270 @ 4 m/s, complex
	cloud distribution

1536	Lat 8.1, Swell from WSW mostly parallel to the wind (here
	260 @ 4-5 m/s)

1537	Passed right over TAO buoy at 8 N

1539	1st BT from 1000', Signal good to 400 m

1541	In rain

1544	CP away at 185-188 knots, bad drop

1546	CTD away, good drop

1552	BT away at 4000' and 192 knots, good drop (lost signal at
	220-240 m depth when aircraft at about 600' on descent)

1555	Lat 6.9, Varied population of clouds in BL, Winds 230 @ 7 m/s

1558	Some whitecaps

1602	Lat 6.6, cloud bases about 400 m, tops 700-1000 m, other decks
	at 1.5-2 km

1605	BT away, bad drop; K-H billows in distance in clouds aloft

1610	CP away from 1600 m (Bad, did not turn on)

1612	CTD away (Good but noisy below 300 m)

1616	BT away from 1600 m (Good)

1622	Lat. 5.3, 100', some whitecaps, Wind 195 @ 7.7 m/s, SST - TA 2.8

1628	Lat 5.06, TAO buoy spotted

1629	Beginning ascent, approaching rain

1632	BT away, good to 380 m

1636	CP away, good

1638	CTD away, good

1639	Lat 4.5, 5000', q about 12 g/kg, clouds at 4.5 km

1642	BT away, bad (never turned on)

1646	Lat 4.0, Descending through BL clouds

1648	Large sheet of As w/ base at 4.5 km, ABL clouds between 1.2-1.3 km

1649	Lat 3.8, start of 100' leg, wind 191 @ 7-8 m/s, SST - TA 2.5,
	mostly LGT chop, q about 14 g/kg (1-2 g/kg less than previous 100')

1652	Lat 3.7, approaching S edge of As shield, passed TAO buoy

1654	Lat 3.56, beginning ascent

1657	BT away (bad), passing through shallow fair-weather Cu

1659	Lat 3.3, CLR OVHD

1701	CP away at 185-188 knots (good)

1703	CTD away (Good to about 400 m)

1705	Lat 3, 5000', Quite uniform tops of BKN-OVC Cu and Sc underneath

1708	BT away (Good to 280 m)

1710	Entering BL cloud on descent, stratus appears to be decoupled
	from lower Cu, some sizable holes in clouds

1715	Lat 2.45, start of 100', SST - TA 4, Wind 180 @ 7 m/s, BKN Sc
	OVHD, some clouds at 300-500 m and 1-1.3 km

1725	BT away, good to 380 m

1729	CP away at 182 kts, good

1731	CTD away at 185 kts, good but noisy below 200 m

1732	Lat 1.5, over fairly uniform stratus

1736	BT away (bad), beginning descent, inversion at 1100-1200 m

1738	Lat 1.1, into cloud

1740	Noticeable variability in height of cloud base

1741	CLR patches OVHD

1743	Lat 0.8, start of 100', SST 25.2, TA 21.5, Wind 170 @ 6 m/s,
	LGT Chop

1750	Lat 0.4, Possibly encountered light drizzle

1752	BT away at 184 kts.(bad)

1754	Lat 0.2, fairly prominent dry layer between 1100 and 1200 m on ascent

1756	CP away at 183 kts. (Bad)

1803	Lat -0.3, BT away (Bad), start descent, CLR OVHD

1806	Extra BT away from 3000' at 220 kts. (Bad)

1807	Lat -0.5, Cloud tops at 630 m on descent

1809	Less turbulence on descent, cloud bases typically near 100m,
	SST 19, TA 18.5, continuous weak stability below 650 m from descent

1811	Lat -0.75, swell from S, wind 130 @ 5 m/s, very light turb

1812	Very low cloud bases, looks like DZ- in region

1815	Into sea fog near end of 100' N-S leg

1820	Lat -1, start ascent, during ascent wind max near 700 m, S wind
	gone by 1000 m, no strong inversion, BL pretty well-mixed in q
	and thetae

1835	Lat 0.0, Ist sonde no winds, repeated at 0.16 N

1850-1857  Uniform cloud tops at around 600 m between 1.5 and 1.8 N from SABL

1905	Lat 2.0, low-level clouds in complex patterns, winds aloft 195 @ 5 m/s

1925	Lat 4.0, OCNL thin layers of stratus over BL Cu and Sc, wind aloft
	250 @ 5 m/s, some lower clouds at 200-300 m, and at 500 m

1929	Picking up BL clouds with tops at 1.1 km

1954	Lat 6.3, winds 255 @ 8 m/s, approaching convection w/ an old anvil
	to the east of the plane

2008	Lat 7.5, OCNL clouds at 5 km, 1.8-2.2 km, 1.3 km, 500 m

2054	Lat 11.1, widely SCT Cbs

2105	Lat 12.0, last sonde (all worked but first), turn for HUX

2121	Lat 13.3, Extensive Ci debris

2203	Landing