# Presentation: 305719

## Microwave Temperature Profiler (MTP) Status Report

**MJ Mahoney**
**Jet Propulsion Laboratory, California Institute of Technology,**
**Pasadena, CA**
**CAMEX-4 Workshop**
**New Orleans, LA**
**March 13 -15, 2002**

## ER-2 Microwave Temperature Profiler (MTP)

**ER-2 Microwave Temperature Profiler (MTP)**

-  Jan 18, 2002 mjm

- ER-2 on the ramp at JAX NAS during CAMEX-4. Photo Credit: mjm

-  PI: MJ Mahoney, Jet Propulsion Laboratory, California Institute of Technology
-  MTP measures the temperature profile above, below & at flight level by observing the natural thermal emission from oxygen molecules between 55 and 59 GHz
-  MTP Heritage: >500 Flights (>3000 Flight Hours)
-  MTP Sensor Unit and Data Unit are located on right engine cheek (see figure)

## Microwave Temperature Profiler (MTP)

- Jan 18, 2002 mjm

- Derived geophysical products:
-  Temperature profiles along the flight track
-  Tropopause altitude
-  Lapse Rate
-  Isentrope () surfaces
-  Science objectives
-  Provide mesoscale meteorological context for *in situ* measurements
-  Assimilate into meteorological models
-  Use derived isentrope surfaces to study dynamical phenomena
-  Data availability and analysis plan
-  Within <1 hour after data taken from a/c
-  Final data within 6 months of end of deployment

**An example of an altitude temperature profile (yellow trace) from 8-28 km (left) or 28-91 kft (right), with the temperature in Kelvin along the bottom. The ER-2 altitude is the horizontal white line at 20 km and the tropopause altitude is dash-ed white line at 15 km. The 2 K/km WMO criter-ia is also shown descending below the tropopause.**

## ER-2 Microwave Temperature Profiler (MTP)

- Jan 18, 2002 mjm

- An example of a MTP-derived temperature field along ER-2 flight track over TS Humberto during CAMEX-4. Black trace is ER-2 pressure altitude, and white trace is the tropopause altitude. The temperature scale is color-encoded in the bar to the right from 190-230 K. Vertical white stripes are data edited out because of radio frequency interference.

- ER-2

- Tropopause

## Microwave Temperature Profiler (MTP) Status

- Jan 18, 2002 mjm

**Report on ER-2 MTP Data and Data Analysis**
-  Heavy & weak interference - typically 20-25% of each flight

## An Example of Interference Seen on an ER-2 CAMEX-4 Flight

**An Example of Interference Seen on an ER-2 CAMEX-4 Flight**

- Entire Flight
- Vertical Tic ~25 K

- 25-X Zoom
- Vertical Tic
-  ~1 K

## Microwave Temperature Profiler (MTP) Status

- Jan 18, 2002 mjm

**Report on ER-2 MTP Data and Data Analysis**
-  Heavy & weak interference - typically 20-25% of each flight
-  Nav Data Recorder Outside Air Temperature is *too warm*
-  Based on RAOB comparisons, the required correction is:  -1.51  0.36 K

## ER-2 Nav Data Recorder Temperature Calibration

-  Thirty-one (31) RAOB comparisons in total from five CAMEX-4 ER-2 flights
-  Passes over the same site were averaged unless the altitude differed by >1.5 km
-  Result is that OAT**nav** is too warm, correction = -1.51  0.36 (N=22)

**ER-2 Nav Data Recorder Temperature Calibration**

## Microwave Temperature Profiler (MTP) Status

- Jan 18, 2002 mjm

**Report on ER-2 MTP Data and Data Analysis**
-  Heavy & weak interference - typically 20-25% of each flight
-  Nav Data Recorder Outside Air Temperature is *too warm*
-  Based on RAOB comparisons, the required correction is:  -1.51  0.36 K
-  Nav Data Recorder (NDR) Pressure Altitude (Zp) is *too low*
-  The error is 400-600 meters (~3-5 hPa) at 21 km
-  Procedure developed to reduce this error to <100 meters
-  Impact is to increase MTP retrieval error significantly if error is >100 meters

**http://mtp.jpl.nasa.gov/missions/camex4/Science/NDR_Corrections.html**

## Slide 10

## An Example of the Erroneous ER-2 Nav Data Recorder Pressure Altitude

-  Note that error is larger on descent than on ascent
-  A large discontinuity occurs at ~8.5 km when switching from fine to course sensor

## ER-2 Microwave Temperature Profiler (MTP)

**ER-2 Microwave Temperature Profiler (MTP)**

- The ER-2 Environmental Control System (ECS) Pressure Profile
-  ECS is under differential control mode for useful Zp (green)

## ER-2 Microwave Temperature Profiler (MTP)

**A Model for a Static Pressure Leak**

- _In addition, due to the finite response time of the ECS, there is a temporal correction, UTcorr:_
-  On ascent, Pi - Po > 3.88 psi + Pcorr
-  Therefore, the pressure altitude (Zp) is even further _under-estimated_
-  On descent, Pi - Po < 3.88 psi + Pcorr
-  Therefore, the pressure altitude (Zp ) is even further _over-estimated_

**Equation to correct NDR pressure altitude, Z'p:**
- Z**'**p(km) = fPtoZ( fZtoP(Zp) + Pcorr ) ) + UTcorr( UT - UTtakeoff )/3600 + Zoffset
- where Zp is in km; UT is in seconds; Pcorr , UTcorr, and Zoffset vary from flight to flight; and the functions fPtoZ(p) and fZtoP(Z) convert between pressure and pressure altitude.

- _Under perfect ECS differential control mode:_
-       Pi - Po = 3.88 psi = 267.44 hPa
- Therefore, a leak will produce a constant
- increase, Pcorr, in the measured pressure Pp.

## Model for pressure leak does an excellent job of correcting error (orange)

- Model for pressure leak does an excellent job of correcting error (orange)

## Slide 15

## Slide 16

## Slide 17

## Slide 18

## Slide 19

## Slide 20

## A 600 meter error in Zp significantly degrades MTP retrievals (green)

- A 600 meter error in Zp significantly degrades MTP retrievals (green)

## Some science results

**Microwave Temperature Profiler (MTP)**

##  Waves appear to be present in the MTP horizon TBs (77 ks & 82 ks)

- A goal for the MTP observations is to study mesoscale wave phenomena
-  Waves appear to be present in the MTP horizon TBs (77 ks & 82 ks)
-  Mesoscale fluctuations appear to be greater than on transit flight (next slide)

## Slide 24

## MTP-derived isentrope surfaces for Hurricane Humberto flight of 2001.09.24

-  Note low amplitude waves at ~77 ks and 82 ks

## Focussing on 480 K isentrope clearly shows low-amplitude mesoscale waves over 

- Focussing on 480 K isentrope clearly shows low-amplitude mesoscale waves over
- Hurricane Humberto; solid black trace shows synoptic scale isentope surface

## There do not appear to be any mesoscale waves present in the ER-2 transit flight

## ER-2 Microwave Temperature Profiler (MTP)

**ER-2 Microwave Temperature Profiler (MTP)**

- Hurricane Humberto - 2001.09.24
- Expect:      MFA = 100 meters
- Measure:   MFA = 120 -130 meters

- The Mesoscale Fluctuation Amplitude (MFA) is the full-width at half-maximum of
- the histogram of mesoscale temperature fluctuations in meters. It depends on altitude,
- latitude, season and topography, and can be expressed as:

- Transit: JAX to DFRC - 2001.09.26
- Expect:      MFA = 118 meters
- Measure:   MFA = 115 meters

## Microwave Temperature Profiler (MTP) Status

- Jan 18, 2002 mjm

**Report on ER-2 MTP Data and Data Analysis**
-  Heavy & weak interference - typically 20-25% of each flight
-  Nav Data Recorder Outside Air Temperature is *too warm*
-  Based on RAOB comparisons, the required correction is:  -1.51  0.36 K
-  Nav Data Recorder (NDR) Pressure Altitude (Zp) is *too low*
-  The error is 400-600 meters (~3-5 hPa) at 21 km
-  Procedure developed to reduce this error to <100 meters
-  Impact is to increase MTP retrieval error significantly if error is >100 meters

**Report on DC-8 MTP Data and Data Analysis**
-  Excellent data set, some interference but very much less than on ER-2
-  Analysis not funded

**http://mtp.jpl.nasa.gov/missions/camex4/Science/NDR_Corrections.html**

## DC-8 MTP clearly sees a temperature anomaly associated with transects of

- Hurricane Humberto on 2001.09.23 and 2001.09.24 (next slide)

## = Temperature anomaly associated with passage through the eye 

- = Temperature anomaly associated with passage through the eye
-    of Hurricane Humberto on 2001.09.24

## Transects of Hurricane Humberto are associated with ~3 K temperature anomaly

- and decrease in the lapse rate to near dry adiabatic (~ -10 K/km)

## In contrast to the Humberto flights, the DC-8 circumnavigation of Hurricane

- Erin on 2001.09.10 shows very little variation in temperature and lapse rate

## Slide 34

## Note increase in temperature and decrease in lapse rate as Hurricane Erin

- is approached (~55 ks) and departed (75 ks).

## Plans for FY’02 and FY’03

**FY’02 Plans:**
-  Complete analysis of ER-2 MTP data
-  Submit to archive within 2 months
-  Collaborate with other CAMEX-4 PI’s as much as possible
-  Carry out independent research to study wave phenomena associated with convection (with collaborator, Dr. Joan Alexander, CoRA)

**FY’03 Plans:**
-  No funding requested for FY’03; therefore, no plans

**Acknowledgements:**
-  Dr Ramesh Kakar for ER-2 support, Bruce L Gary for assistance with the data analysis, and Richard Denning for instrument support.

## Backup

**Microwave Temperature Profiler (MTP)**

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