ASAP Satellite-based tropopause fold and mountain wave detection and validation

Transcription

1 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

2 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)

3 CAT and tropopause folds Upper-air front 150 stratosphere 14 Pressure (hpa) subtropical air mass front tropopause polar air mass 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,

4 GOES specific humidity product WV AWV (WV channel) (specific humidity product)

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7 Building a statistical model Operation of the Model latitude decreasing specific humidity longitude Cloud-masked

8 Building a statistical model Operation of the Model latitude decreasing specific humidity longitude Smoothed (σ = 0.30 )

9 Building a statistical model Operation of the Model latitude Gradient magnitude longitude

10 Building a statistical model Operation of the Model latitude longitude Laplacian zero-crossing

11 Building a statistical model Operation of the Model latitude decreasing specific humidity longitude Extend out 234 km toward the warm air mass

12 Building a statistical model Estimating dimensions of a fold AWV gradient magnitude above the threshold (K) (mean) Length of corresponding tropopause fold (km) Tropopause fold size and water vapor gradient are uncorrelated

13 Web product: Real-time pirep validation Pirep data is provided courtesy of NCAR Aviation Digital Data Service (ADDS)

14 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

15 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.

16 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?)

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18 Building a statistical model Lidar validation (TOPSE, 2000) Tropopause folds were measured at crossings of uppertroposphere air mass boundaries

19 Building a statistical model Hypothesis: Is flux and size of a TF proportional to the AWV gradient magnitude above a threshold?

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21 Also mention: there is potential in studying the affect of plain gradients in the image

22 Introduction GOES imagery AWV product (surface) (upper troposphere ~8 km high)

23 Introduction Elements of Strat-Trop Exchange (STE) streamers (upper-tropospheric air mass boundary) 150 stratosphere 14 Cut-off Low Pressure (hpa) subtropical air mass Polar front (~100 km) tropopause polar air mass Height (km)

24 CAT-prediction with the GOES water vapor channel

25 Zenith angle bias on the water vapor channel

26 Temperature bias on the water vapor channel

27 Combined bias

28 Result: Specific humidity product

29 Building a statistical model Estimating dimensions of a fold The size and length of TFs observed in the lidar were estimated as trapezoids

30 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 N Changes from Mar-Apr, Apr-May

31 Newell et al., 1997, Nature: (~80% of area) 1 km z x (free troposphere) (~11% of volume)

32 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

33 Quantitative validation Gradient /tropopause fold relationship was confirmed quantitatively

34 Quantitative validation TOMS transects The same analysis was performed with Level 2 TOMS total ozone

35 Building a statistical model Estimating ozone in a fold ITGM (K) 3 2 R 2 = ITGM (K) 3 2 R 2 = 1E ozone in fold (kg/m) 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.

36 Streamer fragmentation and tropopause folding in the GOES viewing domain JD 034

37 Streamer fragmentation and tropopause folding in the GOES viewing domain JD 034

38 Streamer fragmentation and tropopause folding in the GOES viewing domain JD 065

39 Streamer fragmentation and tropopause folding in the GOES viewing domain JD 086

40 Streamer fragmentation and tropopause folding in the GOES viewing domain JD 122

41 Streamer fragmentation and tropopause folding in the GOES viewing domain JD 144

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43 Introduction TOPSE* campaign Feb 4 May 23, deg N 7 deployments 10 flights that measured air mass boundary crossings *Tropospheric Ozone Production about the Spring Equinox

44 Introduction TOPSE mission Lidar measurements of ozone

45 GOES WV, 1pm today

46 GOES WV UT specific humidity