| Type of case | cumulus | ||||||
| Complexity | moderate | ||||||
| Convection | convective | ||||||
| Electric field kV/m | Min Em_m = 0.059 Max Em_m = 43.653 Mean Em_m = 11.047 | ||||||
| Microphysics #/Liter |
| ||||||
| Location | (x,y) ~ (-10,40) | ||||||
| Storm Motion | 2.7 m/s east, 1.1 m/s south, gives: 2.9 m/s SE | ||||||
Brief Description | It looks like this slows down as it approaches the coast. |
| Type of case | anvil | ||||||
| Complexity | moderate | ||||||
| Convection | no convection | ||||||
| Electric field kV/m | Min Em_m = 0.439 Max Em_m = 0.439 Mean Em_m = 0.439 | ||||||
| Microphysics #/Liter |
| ||||||
| Location | (x,y) ~ (-60,-10) | ||||||
| Storm Motion | 0.7 m/s east, 2.9 m/s south, gives: 3.0 m/s SE | ||||||
Brief Description | comment |
| Type of case | debris | ||||||
| Complexity | moderate | ||||||
| Convection | no convection | ||||||
| Electric field kV/m | Min Em_m = 0.299 Max Em_m = 0.307 Mean Em_m = 0.303 | ||||||
| Microphysics #/Liter |
| ||||||
| Location | (x,y) ~ (-40,30) | ||||||
| Storm Motion | 6.9 m/s east, 3.5 m/s south, gives: 7.7 m/s SE | ||||||
Brief Description | This used to be the convection that created the anvilin Case 2 |
| Type of case | cumulus | ||||||
| Complexity | moderate | ||||||
| Convection | covection | ||||||
| Electric field kV/m | Min Em_m = 0.121 Max Em_m = 0.121 Mean Em_m = 0.121 | ||||||
| Microphysics #/Liter |
| ||||||
| Location | (x,y) ~ (-10,10) | ||||||
| Storm Motion | 0 | ||||||
Brief Description | Back through case 1? |
Investigator: Jim Dye
[presented on Jan. 22, 2003]
Flight Summary
Case 1 (~1737 to ~1935)
|
Type of case
Complexity Convection Electric field Precipitation Location Focus Studies |
active convection with small anvil moving to south
many small cells of moderate intensity yes, active strong to moderate precipitating in many regions throughout the flight directly over and to west and northwest of KSC good for comparison with KSC Sfc Field Mills -- passes at both 7 and 1.5 km |
|
Type of case
Complexity Convection Electric field Precipitation Location Focus Studies |
decayed debris and anvil
this region inactive but active convection with lightning nearby not in this debris very weak no directly over KSC and to west time of E field decay from last lightning |
Instruments
|
WSR74C Radar
NEXRAD KMLB LDAR CGLSS KSC Ground mills Airborne mills FSSP 2-DC HVPS CPI GOES |
possible Radome atten. after 1945, probably no significant precip atten.
OK OK OK OK OK OK, but early in flt. and at low altitudes, frequent FSSP but little 2D not much 2D at low altitude, may or may not be a problem, otherwise OK OK OK some images |
Brief Summary:
The satellite photos below show a broad area of convection over and to the west of
Kennedy Space Center. The A/C worked two different regions of this complex cluster
of small but moderate intensity cells which had radar tops at times to 15 km and produced
lots of lightning. Case 1 was flown for the most part directly over Kennedy
Space Center and the surface field mill network. Passes were made in and out of very active cells
in which lightning frequently occurred. Aircraft passes were made first
at 7 km and then the aircraft descended to make passes below the active convection
at 1.5 km. The E field measurements from these passes should be interesting to
compare with the Surface E fields from the KSC network.
For Case 2 the aircraft studied decaying anvil or debris from previous convection
a little west of the active convection of Case I. The electric fields in this
region were very weak by the time the aircraft began to investigate it.
LARGE AREA VISIBLE:
vis_1745
vis_1815
vis_1845
vis_1945
EXPANDED:
Florida_1745
Florida_1845
Florida_1945
METEOROLOGICAL OVERVIEW (LINK to be added)
Case I
1730 to ~1935
From 1730 to 1820 the A/C passes were made at 7 km in different parts
of the cellular complex, sometimes over or through the convective cores and
sometimes in weaker reflectivities from outflow or anvil.
Throughout this period lightning was occurring in the region, sometimes close to
the A/C. Consequently E fields were frequently large.
Filtering of the data to remove Citation measurements within +/-20 km and +/-5 min
of lightning (any LDAR source or CG flash) removed all points between ~1728 to 1900.
At approximately 1746:28 the aircraft was struck by lightning. As seen in
the MER plot below, M_Emag reached a peak of ~75 kV/m and the aircraft was
on the edge of a cell with reflectivities of 50 to 55 dBZ at about 5 km.
The 1745-1748 CAPPI without lightning shows the aircraft passed almost directly
over a small, active cell. The CAPPI with lightning shows both LDAR activity
and a CG flash near that location.
MER plot 1740 to 1750
74C CAPPI w/o Lightning 1745 to 1748
74C CAPPI w Lightning 1745 to 1748
The CAPPIs and MER plot below show somewhat typical passes of the A/C as
it flew near the active convection and then out to the north in regions
of mid and upper level debris with weaker reflectivities and weak E fields.
MER plot 1800 to 1810
74C CAPPI w/o Lightning 1804 to 1806
74C CAPPI w Lightning 1804 to 1806
LOW ALTITUDE PASSES NEAR KSC
Between 1820 to 1830 the A/C descended to 1.5 km where a
number of low passes were made from 1830 to 1855 at 1.5 km
below or beside the cells. From ~1843 to ~1850 the A/C flew
pretty close to KSC, along or parallel to the coast.
This may be a good opportunity to compare E fields aloft with those
at the surface with substantial radar reflectivity aloft..
MER plot 1840 to 1850
74C CAPPI w/o Lightning 1846 to 1848
74C CAPPI w Lightning 1846 to 1848
Natalie Murray provided this plot showing some of the electric fields measured
by some of the KSC field mills. Other plots from Natalie will be added.
They show frequent (almost constant) field changes due to nearby lightning.
010607sfcFM.gif
Case II
~1936 to 2007
This was a study of a decaying anvil in which E fields had already
decayed to weak values by the time of the first pass.
MER plot 1930 to 1940
74C CAPPI w Lightning 1938 to 1941
MER plot 1940 to 1950
74C CAPPI w Lightning 1946 to 1949
The last lightning from the convection which produced this debris
was ~1830
74C CAPPI w Lightning 1827 to 1830
So time from last lightning ~1830 to weak E fields is <70 min,
(1940 - 1830). However, there had not been significant lightning
activity in this anvil debris since before 1710 with most of
the active lightning occurring from 1645 to 1700 as this anvil
was first being formed.
74C CAPPI w. lightning 1655-1658
I have a question on validity of CGLSS flashes for this day/period
lightning 1940 to 1950
SCATTER PLOTS of Emag vs. REFLECTIVITY PARAMETERS
In spite of the aircraft being very near lightning for the first hour and a half of
the flight (i.e. until ~1900) and sometimes afterwards as well, the
scatter plots for this case are very well behaved.
The plots for the entire flight data set for the Box 5 and Box 10
averages are shown below.
M_Emag vs Avg dBZ for Box 5
M_Emag vs Avg dBZ for Box 10
Scatter plots using the filtered data set will be added later.
END OF SYNTHESIS
