Mobile Integrated Profiling System (MIPS)
Observations of Boundary Layer and Water
Vapor Variations around Boundaries and Storms
Kevin Knupp
University of Alabama in Huntsville
IHOP_2002 Spring Science Workshop
3/24/03-3/26/03
MIPS - Mobile Integrated Profiling System
IR
radiometer
Lidar ceilometer
Surface
rumentation
Doppler
sodar
Microwa
Profilin
Radiome
915 MHz
Doppler Profiler
18 June 200
Deployment
Analysis activities at UAH
• Examination of the characteristics of all boundaries that
passed over the MIPS (Ph.D. student) - see poster
• 15 June case study (M.S. student, this presentation)
• Heat burst event on 20 June around 0200-0230 Z (Knupp)
– very dry air within the heat burst (T  35 °C, Td  0 °C)
– combination of multiple microbursts and vortices
– Highly variable wind, peak gust to 33 m s-1, near encounter
with a vortex
• Examination of a boundary layer entrainment event on 19
June; observed at the end of the CI experiment
• Examination of the performance of the microwave
profiling radiometer (entire research team)
– focus on the BLE days
15 June 2002 case summary
• 15 June 2002, 1900-2400 UTC
• Observations of a complicated, diffuse boundary
with small thermodynamic contrast. Three
deployments were made around this boundary.
• Continuous observations were acquired as the
eastward-moving boundary intersected the
inflow zone of an existing intense thunderstorm
– the boundary assumed a much better definition
– enhanced inflow into the storm (blowing dust) was
observed
– a strong gust front and outflow occurred 30 min later
Data presentation - 15 June case
• 915 MHz Profiler (Dz = 60 m, Dt = 30-60 s)
– Vh, W, SNR (Z and Cn2), Doppler spectra, Tv(z)
• 0.905 mm lidar ceilometer
– cloud base & precip. properties (extinction), aerosols
• Microwave Profiling Radiometer (to 10 km)
– T(z), rv(z), PW, ILW, cloud base T
• Surface instrumentation (1 Hz)
– T, RH, p, wind, solar radiation
• S-Pol Z
• GOES-11 visible images
(Dt = 14 min)
GOES 11 overview
Good definition in cloud field
1934
2003
Poor definition in cloud field
2034
2103
Anvil moves over the boundary
2134
2203
Intense storm with gust front over MIPS
2255
2334
3 deployments (surface data)
1
2
3
T, Td
Wind
speed
Wind
direction
boundary
Anvil
overhead
Solar
radiation
Radiometer values of PW and ILW (note time breaks)
mm
45
40
1
Profile
2
Systematic
decrease
3
Systematic increase
35
30
25
20
15
10
5
19
:1
9:
47
19
:3
3:
47
19
:4
7:
52
20
:5
0:
55
21
:0
4:
54
21
:1
8:
57
22
:1
8:
12
22
:3
2:
13
22
:4
6:
13
23
:0
0:
12
0
Deployments 1 and 2
1
2
Dep 1: Primarily west
of boundary
Dep 2: Boundary
passage - wind direction
change
Lack of thermodynamic
contrast in both cases
More significant clouds
during boundary
passage at 2055 UTC
boundary
Deployment 1
+
MIPS
Deployment 2
MIPS
+
Winds from
one set of 3
beams, plotted
every 5 min
Red arrows indicate boundary location
915 MHz profiler
Deployment 1
SNR
Updraft with bndy
at 1910?
(deployment 1)
Enhanced SNR
during bndy
passage near 2050
Appears to be a
difference in CBL
properties for 1 and
2 (all moments)
W
sV
Deployment 2
Ceilometer: Cu cloud base near 1.8-2.0 km, some variation in
backscatter at low levels associated with boundary passage
1
clouds
Cloud base decrease
following boundary passage
2
clouds
Radiometer T, rv profiles at 1933
Gd
1922
1921
east
500west
700
west
1000
east
Deployment 3
Boundary passage near
2205 UTC? Oscillation?
Intense vortex observed 2
km to the west.
Anvil passage overhead
rapidly reduced surface
heating. As a result, the
CBL turbulence
weakened.
T, Td
Wind speed
Wind direction
boundary?
pressure
Enhanced inflow into the
approaching storm
Gust front passage at
2256 UTC. 2 mb pressure
rise prior to arrival
solar
Gust front
MIPS
MIPS
+
MIPS
+
MIPS
+
MIPS
+
Deployment 3
Reduction in CBL
turbulence due to
cessation of surface
heating.
Updraft activity
near 2240 UTC
Acceleration of
flow into the storm
Gust front passage
at 2256 UTC - max
updraft > 10 m s-1
and peak gust to 28
m s-1
T, rv profiles at 2246: disappearance of the stable layer
Deeper layer of
water vapor
within the
boundary zone;
35% increase in
integrated vapor
2137
500
700
1000
2220 (same location)
Summary & future work
• Subtle variations in ABL properties were measured across
the diffuse boundary.
• A strong cap existed near 2 km AGL initially.
• The cap eroded within the “sharpened” boundary zone near
an approaching storm. Low-level water vapor increased
significantly within the boundary zone.
• The (main?) boundary appeared to contract as the storm
approached, following a rapid reduction in solar heating.
The storm intensified in the region where it intersected the
boundary. What were the physical mechanisms?
• Future: comprehensive case study; combine sensors to
retrieve more detailed T and rv profiles.
End
Information on MIPS, with a (future) link to
IHOP analysis efforts is at the following site:
http://vortex.nsstc.uah.edu/mips
915 MHz SNR - varied examples, 2/16/01
Ceilometer backscatter: cloud structure,
precipitation properties, BL structure
MIPS measurements of a boundary
(dry line) during IHOP