ASAP Satellite-based tropopause fold and mountain wave detection and validation Tony Wimmers, Kristopher M. Bedka, Wayne Feltz, Nathan Uhlenbrock Cooperative Institute for Meteorological Satellite Studies (CIMSS), UW-Madison John R. Mecikalski, Todd A. Berendes, Udaysankar S. Nair University of Alabama in Huntsville 2005 NASA ASAP Science Meeting, Boulder, Colorado
Topics Synoptic-scale CAT prediction with the GOES water vapor channel Analysis of lee (mountain) wave turbulence with MODIS Automation of gravity wave detection and convectively induced turbulence at UAH (John)
CAT and tropopause folds Upper-air front 150 stratosphere 14 Pressure (hpa) 200 300 400 500 600 700 subtropical air mass front tropopause polar air mass 12 10 8 6 4 Height (km) (~100 km) From Shapiro, M. A. (1980): Turbulent mixing within tropopause folds as a mechanism for the exchange of chemical constituents between the stratosphere and the troposphere, J. Atmos. Sci., 37, 994-1004.
GOES specific humidity product WV AWV (WV channel) (specific humidity product)
Building a statistical model Operation of the Model latitude decreasing specific humidity longitude Cloud-masked
Building a statistical model Operation of the Model latitude decreasing specific humidity longitude Smoothed (σ = 0.30 )
Building a statistical model Operation of the Model latitude Gradient magnitude longitude
Building a statistical model Operation of the Model latitude longitude Laplacian zero-crossing
Building a statistical model Operation of the Model latitude decreasing specific humidity longitude Extend out 234 km toward the warm air mass
Building a statistical model Estimating dimensions of a fold AWV gradient magnitude above the threshold (K) 6 5 4 3 2 1 0 (mean) 0 100 200 300 400 500 600 Length of corresponding tropopause fold (km) Tropopause fold size and water vapor gradient are uncorrelated
Web product: Real-time pirep validation Pirep data is provided courtesy of NCAR Aviation Digital Data Service (ADDS)
Web product: Real-time TAMDAR validation TAMDAR (Tropospheric Airborne Meteorological Data Report) is part of the Great Lakes Field Experiment Data available from MADIS (Meteorological Assimilation Data Ingest System) at FSL Unfortunately, it is mostly lower and midtroposphere
Preliminary Results: Trop folding + CAT From inspection, the model definitely shows skill. So far, the connection between trop folds and CAT appears to be with light to moderate turbulence. The only cases connected to severe turbulence so far are when a tropopause fold creates a capping inversion that later gives way to rapid convection. It is uncertain how much of the predicted turbulence is actually clear (since much of it is under cloud, and the pireps usually don t report visibility). The model appears to validate pilot reports better than TAMDAR (automated) data, perhaps because TAMDAR data does not normally reach the upper troposphere.
Future work: Trop folding + CAT Begin the narrowing down areas of predicted CAT from the current collection (eliminate short folds and folds at weaker gradients). Validate with archived data. Try other fresh approaches as well (for example, do gradients alone predict some turbulence better than the modeled tropopause folds?)
Building a statistical model Lidar validation (TOPSE, 2000) Tropopause folds were measured at crossings of uppertroposphere air mass boundaries
Building a statistical model Hypothesis: Is flux and size of a TF proportional to the AWV gradient magnitude above a threshold?
Also mention: there is potential in studying the affect of plain gradients in the image
Introduction GOES imagery AWV product (surface) (upper troposphere ~8 km high)
Introduction Elements of Strat-Trop Exchange (STE) streamers (upper-tropospheric air mass boundary) 150 stratosphere 14 Cut-off Low Pressure (hpa) 200 300 400 500 600 700 subtropical air mass Polar front (~100 km) tropopause polar air mass 12 10 8 6 4 Height (km)
CAT-prediction with the GOES water vapor channel
Zenith angle bias on the water vapor channel
Temperature bias on the water vapor channel
Combined bias
Result: Specific humidity product
Building a statistical model Estimating dimensions of a fold The size and length of TFs observed in the lidar were estimated as trapezoids
Application to the spring ozone maximum Distribution of TF activity (Feb-May 2000) Maxima in NE Pacific and NW Atlantic around storm track Semi-permanent minimum over Hudson Bay (TOPSE) Dropoff at 35-40 N Changes from Mar-Apr, Apr-May
Newell et al., 1997, Nature: (~80% of area) 1 km z x (free troposphere) (~11% of volume)
Total column ozone AWV-derived moisture troposphere stratosphere high ozone low ozone very low water vapor water vapor Total column ozone and AWV should be closely related (region of AWV response) tropopause break
Quantitative validation Gradient /tropopause fold relationship was confirmed quantitatively
Quantitative validation TOMS transects The same analysis was performed with Level 2 TOMS total ozone
Building a statistical model Estimating ozone in a fold 6 6 5 5 4 4 ITGM (K) 3 2 R 2 = 0.0129 ITGM (K) 3 2 R 2 = 1E-05 1 1 0 0 50 100 ozone in fold (kg/m) 0 0 1 2 3 4 5 6 length of fold (std deg) ITGM Surprisingly, there is no relationship between the intensity of the AWV-derived humidity gradient and the size of the tropopause fold, even though the data shows a strong agreement between large gradients and the existence of tropopause folds.
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 034
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 034
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 065
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 086
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 122
Streamer fragmentation and tropopause folding in the GOES viewing domain JD 144
Introduction TOPSE* campaign Feb 4 May 23, 2000 40 80 deg N 7 deployments 10 flights that measured air mass boundary crossings *Tropospheric Ozone Production about the Spring Equinox
Introduction TOPSE mission Lidar measurements of ozone
GOES WV, 1pm today
GOES WV UT specific humidity