AIRBORNE FIELD MILL PROJECT
KENNEDY SPACE CENTER

SYNTHESIS FOR JUNE 28, 2000 - ABFM

Flight Summary (Flight 1)

Case 1 (Times: 1404 - 1425)
Type of case debris
Complexity moderate
Convection no
Electric field
  kV/m 		Min Em_m = 0.028
Max Em_m = 4.841
Mean Em_m = 0.352
Microphysics
  #/Liter
Max CON_FSSP = 158685.125
Mean CON_FSSP = 2090.085
Max Tot_con_1DC = 7.899
Mean Tot_con_1DC = 0.525
Max Tot_con_2DC = 7.875
Mean Tot_con_2DC = 0.453
Max 2DC_100_400 = 2.324
Mean 2DC_100_400 = 0.155
Max 2DC_400_1000 = 1.083
Mean 2DC_400_1000 = 0.051
Max 2DC_GT_1000 = 0.148
Mean 2DC_GT_1000 = 0.011
Location (x,y) ~ (-20,-40)
Storm Motion 2.9 m/s east, 6.9 m/s north, gives 7.5 m/s NNE

Brief Description

Last lightning occurred about 1305. It is possible the lightning that occurs at 1427, at (-40,-10) is this same cell.

Case 2 (Times: 1425 - 1456)
Type of case debris
Complexity moderate
Convection no
Electric field
  kV/m 		Min Em_m = 0.035
Max Em_m = 0.549
Mean Em_m = 0.139
Microphysics
  #/Liter
Max CON_FSSP = 4025.893
Mean CON_FSSP = 533.339
Max Tot_con_1DC = 62.527
Mean Tot_con_1DC = 10.755
Max Tot_con_2DC = 76.112
Mean Tot_con_2DC = 12.276
Max 2DC_100_400 = 46.689
Mean 2DC_100_400 = 6.120
Max 2DC_400_1000 = 9.994
Mean 2DC_400_1000 = 1.528
Max 2DC_GT_1000 = 0.457
Mean 2DC_GT_1000 = 0.100
Location (x,y) ~ (0,-100)
Storm Motion 2.9 m/s east, 6.9 m/s north, gives 7.5 m/s NNE

Brief Description

Last lightning occurred about 1305.

Flight Summary (Flight 2) (Anvil Day)

Case 3 (Times: 1815 - 1837)
Type of case anvil
Complexity moderate
Convection not at the time of study
Electric field
  kV/m 		Min Em_m = 0.016
Max Em_m = 1.350
Mean Em_m = 0.155
Microphysics
  #/Liter
Max CON_FSSP = 3716.883
Mean CON_FSSP = 527.661
Max Tot_con_1DC = 67.651
Mean Tot_con_1DC = 10.622
Max Tot_con_2DC = 25.155
Mean Tot_con_2DC = 3.536
Max 2DC_100_400 = 10.578
Mean 2DC_100_400 = 1.491
Max 2DC_400_1000 = 6.438
Mean 2DC_400_1000 = 0.879
Max 2DC_GT_1000 = 0.107
Mean 2DC_GT_1000 = 0.014
Location (x,y) ~ (-25, -30)
Storm Motion No core from which to measure storm motion.

Brief Description

The "core" for this case is directly over the radar, inside the "radar void".

Case 4 (Times: 1837 - 2000)
Type of case anvil and convection
Complexity simple
Convection yes
Electric field
  kV/m 		Min Em_m = 0.145
Max Em_m = 55.217
Mean Em_m = 5.611
Microphysics
  #/Liter
Max CON_FSSP = 65747.461
Mean CON_FSSP = 5369.066
Max Tot_con_1DC = 1307.799
Mean Tot_con_1DC = 105.317
Max Tot_con_2DC = 2147.206
Mean Tot_con_2DC = 107.785
Max 2DC_100_400 = 892.142
Mean 2DC_100_400 = 49.466
Max 2DC_400_1000 = 80.662
Mean 2DC_400_1000 = 7.122
Max 2DC_GT_1000 = 3.261
Mean 2DC_GT_1000 = 0.327
Location (x,y) ~ (0,-40)
Storm Motion 6.9 m/s north

Brief Description

The aircraft missed most of the anvil for this case. It was usually sampled when the aircraft was turning around.

Case 5 (Times: 2003 - 2118)
Type of case anvil
Complexity simple
Convection yes
Electric field
  kV/m 		Min Em_m = 0.201
Max Em_m = 48.675
Mean Em_m = 7.597
Microphysics
  #/Liter
Max CON_FSSP = 25327.604
Mean CON_FSSP = 4966.604
Max Tot_con_1DC = 630.031
Mean Tot_con_1DC = 95.715
Max Tot_con_2DC = 936.511
Mean Tot_con_2DC = 60.580
Max 2DC_100_400 = 369.675
Mean 2DC_100_400 = 27.063
Max 2DC_400_1000 = 45.828
Mean 2DC_400_1000 = 4.574
Max 2DC_GT_1000 = 2.468
Mean 2DC_GT_1000 = 0.293
Location (x,y) ~ (-40,0)
Storm Motion 7.6 m/s north, 1.5 m/s east gives 7.7 m/s NNE

Brief Description

The aircraft remained too close to the core when sampling this anvil case.











SYNTHESIS FOR JUNE 28, 2000 - ABFM

Investigator: S. Lewis
[presented on May 2, 2002]


 

 

 

Lightning
WSR74C MER Plots
Microphysics Time Series
Electric Field WSR74C CAPPIs


Flight 1 - 1404 to 1510

Brief Summary

The aircraft arrived too late for anvil decay studies. Although it is a good case for showing that the fields an hour after last lightning were small.
1228
Aircraft moved on SE along the band. We have a 1kV/m fields and less than 15 dBZ reflectivity.
1430_mer_5
Everything is weak.

There were weak fields and small particle concentrations an hour after the last CG.


Full Description

Flight 1 investigated a storm system that consisted of a band of cells that moved NW along the coast line. It moved/grew in a NNW direction, parallel to the coast line (NW and W of Vero Beach). It looks like the convection or new convection is "out running" the anvil. [ 1215 ] [ 1228 ] When you can run the radar as a loop the system appears to decay just before it reaches the cape, then picks up again on the northern edge at KSC. The speed of the whole system is going (on average) about 5.5 m/s up the coast. I believe the the later cells that form over KSC have the same source as the earlier cell system that we are going to focus on for this discussion.

At 1215 [ 1200_1230_lightning ] the system has 3 cellular subsystems (separate regions with reflectivity greater than about 15-20 dBZ). The northern most one has two cores (regions with reflectivity greater than 25 dBZ), the central one doesn't really have a core larger than 25 dBZ, and the southern most has 3 cores. The first CG occurred at 1212, and was located in the northern-most subsystem.

There was IC and CG lightning occurring throughout this band between 1210 and 1330 ( 1230_1300_lightning ). The cloud to ground was occurring in the northern most cellular subsystem. The lightning that occurred in the southern most subsystem appears to be all intercloud.

By 1230 [ 1230_1300_lightning ] the individual cores tend to merge and the northern 2 subsystems also look to be merging. At 1245 [ 1230_1300_lightning ] the second cellular subsystem looks like it might be the anvil of the northern most subsystem. In fact, I believe it was treated as such when the airplane flew. The southern subsystem cores have separated again and a look at the cross-section shows that it does have an anvil. (A special note about the cross-sections. In order to get a cross-section that is oriented along the line of convection I had to rotate the radar data. The *z* plots show the orientation in one z-plane which can be matched up with the cross-section. In order to get the cross-section plots the volume had to be rotated, the horizontal plot that appears with every cross-section will help you orient the cross-section to the features of interest. The naming convention for the cross-sections is: time, y defines the constant plane, and m032 means y = -32) [1244_z4 ] [1244_ym032 ] Both CG and IC lightning occurred throughout the time between 1230 and 1300, although the CG is occurring in the northern most subsystem. CGs continue at a moderate rate from 1212 until ~1250; then there is a gap in CGs until ~1320 when the last CG occurs. About 20 CGs total occurred.

By 1315 [ 1300_1330_lightning ] the anvil in the southern most subsystem continues. [1316_z4 ] [1316_ym030 ] The northern most part of that line is decaying faster than the southern most part of that line. This is probably due to the weaker cores in the northern subsystems.

The aircraft took off at about 1400 and proceeded to go to the system, which was to the south. 1406_mer_5
When it reached the system it did an ascent through the northern-most cloud getting into place for 7 km legs.
1415
1400_1430_lightning
1415_mer_5
1415_E_50
1415_uphys
in the decayed convective region of the northern subsystem [1414_z4 ] [1414_ym030 ] through very weak (non-existent) fields.

Comparing the following radar and lightning images it can be seen that the aircraft ascent was through the "same air" where the last lightning occurred at 1320. Thus in that hour the fields had decayed towards zero.
1315 [ 1300_1330_lightning ]
1415
The next lightning occurred at 1445. By comparing the 1415 radar with 1445 it can be seen that the aircraft did not fly through this building cell, because the cell was north of the flight track.
1445 [ 1430_1500_lightning ]

The MER plots during [ 1420_mer_5 ] show that everything was weak, the |E|-fields, the reflectivity, and the particle concentrations.

At 1423 [ 1427_mer_5 ] the aircraft started to fly along the line at the 7km level though reflectivity about 10-15 dBZ. The fields did not get above 1 kV/m and the total 2dc concentration stayed below 10^2/L for the most part.

After the aircraft reached 7 km it moved SE to fly through the southern most edge of the second subsystem and the northern most part of the third subsystem.
1430
1430_1500_lightning
1430_mer_5
1430_E_50
1430_uphys
This southern most subsystem still had reflectivities above 20 dBZ at the 7 km level, as can be seen by the radar.

Between 1430 and 1445 the aircraft flew through the southern subsystem, although it reached the 20 dBZ reflectivity the fields were weak.
1445
1430_mer_5 , 1430_hor
1438_mer_5 , 1438_hor
1443_E_50
1430_uphys
There is a single flash at 1430 that appears to be associated with the last bits of the northern most cell. The lightning starts again at 1445 - 1630 ++. This lightning is again occurring "at the head of the line" in a region of new convection.

The Electric fields were small for this flight. The MER plots show that during this flight the aircraft did not fly through anything much higher than 15 or 20 dBZ, and the echo tops at the flight location were between 10 and 13 km. But Ez <1 KV/m and N30 ~1-10/L and N1 ~.01 to 0.1 /L.

The A/C then flew back and forth in the anvil SSE - NNW headings until about 1500. Fields were all < 1 KV/m. Observer comments "cloud not very dense". While making the approach to PAFB rapid changes of ~ 1 KV/m characteristic of lightning were seen in Ez and the CGLSS and LDAR show lightning near the A/C.
1446_mer_5 , 1449_hor


At about 1500 the aircraft flew back home, but it appears that it flew east of the system.

This is another questionable call, is it an anvil or is it a convective debris case? I would argue that the area that the aircraft flew through was convective debris.













Flight 2 - 1815 to 2132

Case 3

All passes in these active cells had |E| fields of 10 -15 KV/m or more. Lots of lightning in these storms even where the A/C flew. The flight may not be good for examining decay of |E| with space or time for anvils specifically. It does show that when |E| is >10 KV/m when total 2dc >~10^2 and 2dc > 1mm is >~10^0, and shows decay of convection with anvil.

The storm system that the aircraft studied during the second flight of this day was relatively stationary as determined by looking at the 7 km level. It consisted of several separate subsystems. It started over the cape and the cells that formed tended to grow and decay without much translation (at the 7km level). The first cells of this system started up by
1600 .
There was a cell directly over the cape (something under the radar hole?) at
1600_1630_lightning
that was producing a lot of lightning. A couple of small cells begin to form just to the north (x~0, y~40). There are also cells that are forming to the southwest of the cape along (x~ -50, y~ -80). The lightning data shows all of the cells in the vicinity of KSC are active until about 1700.
[ 1630_1700_lightning ]
The last CG in the cell over the radar occurred around 1643, although there was some IC until about 1710.
[last CG ] [more IC ]


At 1616 you can see the direction that an anvil would blow by looking at the cells to the north.
1616
In fact the cell that is right under the radar also appears to have an anvil extending into the south-west direction.
[1616_z08 ] [1616_ym8 ] [1616_yp0 ] [1616_yp8 ]

The aircraft takes off over an hour after the last lightning and it climbs into the debris of the (or the decayed) anvil of the cell that was right in the radar hole along the trailing (southern) edge.
[ hor_1817 ][ mer_1815 ]
There is no further lightning activity in the cell over the radar. The mer plots show very little cloud or Efield.
[mer spiral 1815 ]
This shows the weak fields, an hour after the lightning activity.

Case 4

As they come out of the spiral they enter the cell to the south which started up at about
1714 [ 1714_07 ]
at (x ~ 0,y ~ -50). The lightning images show that there is IC and some CG starting in this southern cell at about 1725.
[ 1700_1730_lightning ]

The aircraft enters the system at the 7 km level. The electric fields are weak until it enters cloud, then there is a sudden change at 1838 when it flies through and over a 25-30 dBZ region.
[ hor_1836 ][ mer_1830 ]
1830_E_50 (Due to nearby lightning?)

The highest reflectivities (45 or 50 dBZ) either precede the high fields or are simultaneous with strongest fields (stronger than -50 kV/m). These are the strongest fields observed in this system. The fields at this time are negative as the aircraft flies at 8 km.
[ hor_1846 ][ mer_1846 ]

There was plenty of lightning activity (IC and CG) during the time the aircraft was investigating this cell.
1830_1900_lightning shows the flight tracks are right in the heart of the lightning producing region. The last CG occurred in this cell at about 1855, and the IC stopped about 15 minutes later
[last CG ] [more IC ]


Now the strong fields coincide with the stronger reflectivities (45 - 50 dBZ). These strong negative fields are about -40 kV/m.
[ hor_1849 ][ mer_1846 ]


The fields and reflectivity have weakened quite a bit. At 1902 and 1903 the fields still are negative. At 1904 the fields suggest a change in sign but it would take a closer investigation to confirm if it is significant. But by 1906 there is a definitely field change and the aircraft is flying through the anvil.
[ hor_1902 ][ mer_1902 ]

Cross sections show there was a true anvil. There is no longer any CG after 1900, although there some IC until about 1910.
[1910_z07 ] [1910_ym16 ] 1900_1930_lightning

The reflectivity continues to weaken and the fields continue to be positive and relatively strong (about 20 kV/m).
[ hor_1913 ][ mer_1910 ]


By 1919 the aircraft was well into the anvil and the fields were negligible. The last volume of this mer shows relatively strong, positive fields as the aircraft passes the "core".
[ hor_1918 ][ mer_1918 ] [ hor_1923 ]


The aircraft starts to descend to 7 km at 1929. The fields increase again as it flies through a region of 20-30 dBZ.
[ hor_1926 ][ mer_1926 ]


There is a bit of a stronger field as it flies through a small region of 20-25 dBZ. When the aircraft reaches the anvil there are no fields.
[ hor_1934 ][ mer_1934 ]


The system is definitely decaying, existing only in the 7 - 10 km space. The fields are much weaker and they have gone negative again. Some of this change in sign of the fields could be due to subsidence of the charge relative to the aircraft position during the decay.
[ hor_1942 ][ mer_1942 ]


More of the same; the reflectivity continues to weaken as do the fields. At about 1958 the aircraft moves on to the next system.
[ hor_1955 ][ mer_1950 ]


This is a good system to study the evolution of a storm, but the aircraft did not start flying into the anvil until the storm had started to decay. As an ABFM case, the aircraft does fly into the anvil (although not all the way through, therefore, not a priority case). We definitely see the system going from strong to weak fields. We also see the fields turning on and off at the cloud edge. It is probably safe to assume the fields are weaker in the anvil, and that those fields in the anvil mimic the convection.

Case 5

A new system (2 or 3 cells) began to form at about 1929 at (x~ - 50, y~0) between previous systems.
1929
This is the storm that the aircraft flew to investigate at 2000.
2000
by this time it had formed an anvil at 10 km which was blowing off to the southwest.
[2000_z07 ] [2000_yp20 ] [2000_yp28 ] [2000_yp32 ] [2000_yp36 ] shows the nature of the anvil. (x ~ -90 y ~ 30 on the rotated plot, 2000_z07)
There was plenty of lightning in this cell during this time.
2000_2030_lightning
It was into this anvil that the aircraft flew, making several passes from about 2000 to 2100.

The fact that these systems don't move much would suggest that several of those legs went through the "same air". The 4km radar images show that the reflectivity goes at least down to the 4km level in much of this last series of maneuvers. The aircraft arrived at this cell about the same time the lightning activity started in the cell. The lightning activity started to decrease about the time the aircraft left the region.

At 2006, the aircraft flew at an altitude of about 9 km. The fields became more strongly negative (-50 kV/m) when inside the cloud. The CAPPIs show there were stronger reflectivities NE of the flight track at lower levels.
[ hor_2006 ] [ mer_2006 ]

Continuing at the 8 km level, the fields drop off as the aircraft moves into the anvil. The low level reflectivity stops at about 2013, and the fields take a minute longer. (mer_2006 vs mer_2014)
[ hor_2014 ] [ mer_2014 ]

As we have been frequently saying: no reflectivity, no field. I am not seeing the obvious delay in the signal that has been mentioned in previous conference calls.
[ hor_2021 ] [ mer_2021 ]

What are the |E| spikes at 2030? Notice the fields are changing sign as the system goes into decay.
[ hor_2029 ] [ mer_2029 ]

The fields are now predominantly positive and the reflectivity now is sparse at 4 km and mostly at 8 km (flight level).
[ hor_2040 ] [ mer_2037 ]

By 2044 the fields reduce down to zero while the upper level reflectivity decays. 2053 shows the aircraft flew over reflectivity that reached the ground while the electric field increased in magnitude.
[ hor_2045 ] [ mer_2045 ]

There is one pixel of higher reflectivity at 20:57:30, could the increase in |E| be the result of such a small region?
[ hor_2053 ] [ mer_2053 ]

Continue to fly through anvil region with pockets of higher fields, apparently associated with "single Pixel" reflectivity magnitudes of about 25 dBZ.
[ hor_2101 ] [ mer_2101 ]

Decaying anvil, not sure what is causing the |E| blip at 2116.
[ hor_2109 ] [ mer_2109 ]

Landing.
[ hor_2120 ] [ mer_2117 ] [ hor_2125 ][ mer_2125 ]

The 4km level would suggest a slow NE motion of the reflectivity. The 10km level would suggest a motion to the SW, I suspect this could be the anvils blowing off in that direction.

This is an example of a decaying storm, but I am not sure enough anvil work was done to satisfy the ABFM requirements.