NSF C-130 Mission Summary Report (EPIC)

RF08
95W Mission

Summary - Second combined ocean probe/atmospheric profiling mission along 95W.
This flight featured a relatively strong ITCZ, with enhanced low-level
(ABL) southerlies and mid-tropospheric northerlies south of the ITCZ,
relative to the first two flights.  As in the flight of 14 September, the
SST front was marked by little change in cloud coverage (the clouds were
more stratiform south of the front).  In addition, there were again patches
of clouds with very low bases, possibly sea fog, but also possibly just
associated with drizzle, which was observed.  The SST front itself appeared
to be weaker and/or farther north than on the first two flights.  Virtually
no clouds were present above the ABL south of around 5N.  The ocean probe
component was largely successful; 10/12 BT's, 6/7 CTD's and 3/5 CP's
returned reasonable signals.  There are uncertainties about the quality
of the data from the CP's in the southern part of the domain.


Flight Notes

1330	Takeoff

1336	Relatively stable profile on ascent, predominantly Ci clouds
 
1414	Beginning descent into pattern south of 13 N.  Considerable
	haze, SCT fair-weather Cu w/ some penetrative convection

1421	Max wind on descent 110 @ 4 m/s at 2100 m, relatively minor
	and diffuse trade-wind inversion

1427	Start of 1st porpoise, weak SW sfc. winds, thetae 357, q 21
	Spotted 12 N buoys (birds on it). SABL just starting to work

1432	Beginning ascent.  On ascent went through BL clouds with tops
	at 1100 m. O3 reduced compared to previous descent.

1440	Beginning 5000' leg. Wind 115 @ 10 m/s, q 10, some of the
	higher BL clouds have tops just above flight level.

1449	Beginning descent.  Hit clouds at around 1300, 1100 and 700 m.
	Cloud base near 500 m

1459	At 100', minor whitecapping, wind 270 @ 5 m/s, q 18, thetae
	359, SCT-BKN Sc

1507	Flew past R/V Brown; they reported 7" of rain in recent 3 day
	period.  Rain occurred mostly at night.

1510	Entered BL cloud at around 600 m.  Trade-wind inversion (TWI)
	about 500 m thick.  Cb's in the distance south

1519	Lat 9.2, 5000', wind 45 @ 2 m/s, q 11

1521	Through minor towering Cu, max. w about 1 m/s

1523	Beginning descent near 9 N, very near ITCZ Cb's, typical
	w 1-2 m/s

1527	Brief light rain, main cloud base about 550 m, some scud
	below, little sign of a distinct BL and capping inversion
	Descent near modest Cb.

1530	Light rain but little limit to visibility, thetae 353, q 17
	wind 245 @ 8 m/s

1531	Climbing to 500' because of mod/heavy rain and some problems
	w/ radar altimeter, marked decrease in thetav

1535	Two lightning strikes in distance

1536	Exited heaviest precip.

1539	Passed over buoy at 8 N, thetae 359, q 18, wind 200 @ 7 m/s

1543	Lat 7.8, BT away at 195 kts (Good probe)

1546	CP away at 190 kts (Bad)

1548	CTD away at 190 kts (Good)

1551	A few towering Cu in distance (no anvils)

1554	Beginning descent, BT away (good).  Signal noted to 300 m
	depth at which point plane at 600-900'. Some stratus between
	2-2.3 km

1556	Marked drying and increase in O3 from 1400 to 800 m altitude

1558	Entering cloud at 550-600 m, another deck at 300-400 m.

1600	Lat 6.9, below clouds,light chop, SST 27.6, TA 25.8, winds
	208 @ 8 m/s, whitecaps, almost solid OVC @ 2-2.2 km, fairly
	sizable swell

1606	Beginning ascent at 6.5 N, very low cloud bases, DZ/R-

1609	BT away at 192 kts (good)

1611	Lat 6.2, enhanced turb. near top of ascent

1613	CP (Good), currents to 1500 m

1615	CTD (Good), within clouds at 5000', SABL shows tops to 1.8-2.1 km,
	winds 240 @ 3 m/s, q 12, thetae 347, some holes in clouds below

1621	Start of descent, BT (good)

1623	Low-level Cu encountered about 900 m on descent, complicated
	organization to the clouds

1625	Lat 5.5, cloud base 250 m

1628	Lat 5.4, begin 100' leg, wind 195 @ 10 m/s, SST 27.7, TA 26.7
	thetae 345, q 15, breaks in cloud cover, spotted 5N buoy

1633	Lat 5.0, now just BL clouds

1634	Beginning ascent, mostly stratus and Sc clouds

1636	BT (Good)

1638	Moderate chop on ascent until cloud top near 1200 m

1640	CP away at 188 kts (failed)

1642	CTD away at 187 kts (OK but noisy below 300 m)

1643	Considerable holes in undercast of stratus, some SC, winds
	50 @ 3-4 m/s, q 12

1647	Start of descent at 4.2 N, BT (good), entered cloud at 1400 m
	Decent buoyancy (w about 1 m/s), in cloud most of descent until
	hit base at 450 m, from SABL clouds 900-1300 m and 500-1000 m

1653	Start of 100' leg at 3.9 N, SST 27.4, TA 25.5, a bit more turb
	than on previous 100' leg, wind 165 @ 8 m/s

1657	Wind 180 @ 8.5 m/s, thetae 340, q 14

1659	Beginning ascent at 3.6 N, no clouds until 800 m

1701	BT (bad)

1703	Cloud top near 1100 m, marked and thin inversion above, fairly
	uniform stratus from above

1705	CP (good)

1706	Lat 3.2, wind 70 @ 4 m/s, q 11, thetae 343, CLR OVHD

1707	CTD (good but somewhat noisy)

1713	Start descent at 2.8 N, BT (good), cloud top near 1200 m

1715	Lat 2.6, sharp inversion above cloud top, diffuse cloud base at 300 m

1720	Start 100' at 2.4 N, SST 26.6, TA 24.1, wind 170 @ 8.5 m/s, some
	whitecaps, thetae 336, q 13

1724	SABL clouds near 500-700 m, some extending to near surface (DZ-)
	uniform tops

1729	Lat 1.9, BT (bad) cloud base near 450 m

1733	CP away at 185 kts (good)

1734	CTD away at 185 kts (bad), at 5000', Lat 1.6, wind 72 @ 8 m/s,
	thetae 343, q 11, classic-looking shear at the top of the BL
	easterlies above and southerlies below

1739	Replacement CTD away (good)

1742	BT (good), cloud top near 940 m

1748	Lat 0.8 N, start of 100', SST 24.4, TA 22.2, continued stratus
	OVHD, wind 145 @ 7 m/s, q 10-11, thetae 330

1750	Ship spotted, light chop, SABL suggests stratus (rather than Sc)
	OVHD between 500-600 and 700-800 m

1759	End of E-W 100' leg at 0.5 N

1802	Diffuse cloud base near about 500 m, top near 800 m, CLR above

1803	BT (good)

1807 	CTD (good)

1808	Lat 0.0, 5000', wind 90 @ 7 m/s, q 10, thetae 340

1814	Starting descent, BT (good)

1816	Top of Inversion near 1000 m, top of clouds 800 m, broke out of
	stratus near 600 m, other clouds down to as low as 100 m, max wind
	8.5 m/s near 300 m level

1819	Some breaks in OVC

1820	Start of N-S 100' leg, SST 20.4, TA 20.4, Ophir 18.2, q 11
	some small LWC, wind 140 @ 7 m/s, virtually OVC

1824	Light rain or drizzle, tops near 600 m, had to ascend because
	of poor visibility

1829	Wind 150 @ 5 m/s, some breaks in OVC near end of E-W 100' leg

1833	Beginning ascent for inbound ferry, max winds of 8.7 m/s near
	300 m level, inversion between 800 and 1000 m

1843	1st drop at equator good

1856	SABL looks like it has condensation

1901	Lat 1.0 N, winds 325 @ 4 m/s, q 0.4, SABL slowing coming back

1909	Some very light to light chop aloft (not noticed on previous ferries)

1959	Lat 5.5, more varied population of clouds visually and from SABL

2005	Lat 6, skirting Cb

2009	In cloud

2013	Out of cloud

2029	Lat 7.8, light chop, precip in vicnity

2037	Diverting around Cb, still hit 8 m/s updraft, broad region of 2-3
	m/s updrafts on north side

2055	Passed over R/V Brown

2129	All dropsondes good 

2222	Landing