Joint NWS SOO–NASA SPoRT Workshop Huntsville, Alabama 11-13 July 2006 Convective (and Lightning)...

Joint NWS SOO–NASA SPoRT Workshop

Huntsville, Alabama 11-13 July 2006

Convective (and Lightning) Nowcast Products: SATellite Convection AnalySis and Tracking (SATCAST) System

John R. Mecikalski1 (Assistant Professor)Kristopher M. Bedka2

Todd A. Berendes1

Simon J. Paech1

and Laci Gambill1

1Atmospheric Science DepartmentUniversity of Alabama in Huntsville

2Cooperative Institute for Meteorological Satellite StudiesUniversity of Wisconsin-Madison

Supported by:

NASA New Investigator Program (2002) NASA ASAP Initiative

The NASA SPoRT Initiative



Outline

• Current capability: OverviewConvective initiation (CI)

• BackgroundError assessments in Daytime CI 0-1 h NowcastingConfidence analysisIncorporation of MODIS informationDiscriminant scoring for CI --> QPE

• Current & new initiatives: 2006Impacts of microwave data toward 0-2 hour QPE forecastingNighttime CI forecastingLightning (event) & Lightning Initiation forecastingCI/LI Climatology as f(location, time of year)GOES-R Risk Reduction (using MSG & MODIS)



How this began…

••



Methods: Convective Nowcasts/Diagnoses

How is this done?

Determine the necessary data to evaluate convective and lightning initiation from satellite

Is satellite data the best??

If so, how can it be used? Why might it be superior to radar?

A: Satellites “see” cumulus before they become thunderstorms!A: There are many available methods for diagnosing/monitoring cumulus motion/development in real-time (every 15-min). See the published research on satellite data usage !!!

So, once well-read, all the pieces are in place to move the (science) forward in the CI nowcasting arena, with satellite analysis as the centerpiece for 0-1 h CI nowcasting.



Where are we now …

• Applying CI algorithm over U.S., Central America & Caribbean• Validation & Confidence analysis• Satellite CI climatologies/CI Index: 1-6 h• Work with new instruments• Data assimilation possibilities



Convective Cloud Mask

• Foundation of the CI nowcast algorithm: Calculate IR fields only where cumulus are present (10-30% of a domain)

• Utilizes a multispectral and textural region clustering technique for classifying all scene types (land, water, stratus/fog, cumulus, cirrus) in a GOES image

• Identifies 5 types of convectively-induced clouds: low cumulus, mid-level cumulus, deep cumulus, thick cirrus ice cloud/cumulonimbus tops, thin cirrus anvil ice cloud



“Mesoscale” Atmospheric Motion Vector Algorithm

“Operational

Settings”

New Mesoscale

AMVs

(only 20% shown)

• We can combine mesoscale AMV’s with sequences of 10.7 m TB imagery to identify growing convective clouds, which represent a hazard to the aviation community

50% shown



CI Interest Field Critical Value

10.7 µm TB (1 score) < 0° C

10.7 µm TB Time Trend (2 scores)< -4° C/15 mins

∆TB/30 mins < ∆TB/15 mins

Timing of 10.7 µm TB drop below 0° C (1 score) Within prior 30 mins

6.5 - 10.7 µm difference (1 score) -35° C to -10° C


6.5 - 10.7 µm Time Trend (1 score) > 3° C/15 mins


CI Interest Fields for CI Nowcasting

from Roberts and Rutledge (2003)



2000 UTC

2030 UTC

2100 UTC

CI Nowcast Algorithm: 4 May 2003

• Satellite-based CI indicators provided 30-45 min advanced notice of CI in E. and N. Central Kansas.

• PODs ~45% at 1 km (FARs ~40%)

• NEW Linear Discriminant Analysis methods provide ~65% POD scores for 1-hour convective initiation.

CI Nowcast Pixels

These are 1 hour forecasted CI locations!



An Example over the Tropics: CI

An example of the CI nowcasting method over

Central America:

• Real-time

• Every 30 min during the day (nighttime coming soon)

• GOES (MODIS soon)

• RED/GREEN pixels have highest CI probability



“Interest Field” Importance: POD/FARCI Interest Field Critical Value

10.7 µm TB (1 score) < 0° C

10.7 µm TB Time Trend (2 scores)< -4° C/15 mins

∆TB/30 mins < ∆TB/15 mins

Timing of 10.7 µm TB drop below 0° C (1 score) Within prior 30 mins





• Instantaneous 13.3–10.7 um: Highest POD (84%)• Time-trend 13.3–10.7 um: Lowest FAR (as low as 38%)• Important for CI & Lightning Initiation

8.5-10.7 m (MODIS)

> 0° C

> 0° C

3.7-10.7 m (MODIS)



Use of MODIS in Convective Initiation Forecasts



• The lower right shows the supercooled water in green.

• Proof of concept for determining the difference between supercooled water and glaciated towering cumulus clouds.

Super-cooled tops:Lightning indicator as a function of convective

environment



New: CI/LI Linear Discriminant Analysis (LDA)

Some correlation between aconfidence in CI [f(LDA score)] and30-min dBZ (increase): QPE nowcast

• Improved POD of ~65and FAR of ~34%

• A virtual-radar from satellite



New: CI/LI Linear Discriminant Analysis (LDA)

Number of Interest Fields

Radar dBZ t=t+30 min

LD

A S

core

LD

A S

core

Low correlationHigh correlation



Outline

• Current capability: OverviewConvective initiation (CI)

• BackgroundError assessments in Daytime CI 0-1 h NowcastingConfidence analysisIncorporation of MODIS informationDiscriminant scoring for CI --> QPE

• Current & new initiatives: 2006Impacts of microwave data toward 0-2 hour QPE forecastingNighttime CI forecastingLightning (event) & Lightning Initiation forecastingCI/LI Climatology as f(location, time of year)GOES-R Risk Reduction (using MSG & MODIS)



Detecting Convective Initiation at Night

Detection of convective initiation at night must address severalunique issues:

a) Restricted to 4 km data (unless MODIS is relied upon)b) Visible data cannot be used to formulate cumulus maskc) Highly-dense, GOES visible winds are unavailable for trackingd) Forcing for convection often elevated and difficult to detect

(e.g., low-level jets, bores, elevated boundaries)

However, the advantages are:a) Ability to use ~3.9 m channel (near-infrared) data (!!!)b) More “interest fields” become available for assessing cumulus cloud

development

Therefore, new work is toward expanding CI detection fornocturnal conditions, and/or where lower resolution may bepreferred (i.e. over large oceanic regions).

Wayne Mackenzie, MS student




Nighttime CI: SoutheastOklahoma

Enhanced 10.7 m

SHV: 3:44 UTC




Use of 3.9 µm channel:

10.7-3.9 m channel difference (Ellrod “fog” product)13.3-3.9 m6.5-3.9 m

Evaluation is being done in light of the forcing for the convection (e.g., low-level jets, QG).


Huntsville, Alabama 11-13 July 2006 kkoooooooookkkkkkkkkkk

Satellite-Lightning Relationships• Current Work: Develop relationships between IR TB/TB trends and lightning source counts/flash densities toward nowcasting (0-2 hr) future lightning occurrence•Supported by the NASA New Investigator Program Award #:NAG5-12536

• Incorporate in NWS Lightning Hazard/Prediction Tool

2047 UTC

2147 UTC

Northern Alabama LMA Lightning Source Counts

2040-2050 UTC

2140-2150 UTC


Huntsville, Alabama 11-13 July 2006kkkkkkkkkkkkkkk

2040-2050 UTC

2140-2150 UTC

Northern Alabama LMA Lightning Source Counts

Lightning InitiationPotential



GOES CI Interest Fields: 21 July 2005 (afternoon)

CI Climatology Research

Details:-topography-main updrafts

…for LI1 km Resolution



Hyperspectral: GOES-R & GLM

LEFT8.508-10.98 m Band

Difference: Red (’s >0)

= Ice

Comparison between the 10.98

m (right) and 11.00 m (far right) bands:

22 UTC 6.12.2002

Small wavenumber changeresults in significant changesin view: Low-level water vapor Surface temperature Subtle cloud growth& microphysical changes



For the NWS … Real-time use & evaluation

In addition

A web-basedevaluationis beingperformedin a post-shift formatduringJuly andAugust 2006.

Smoothing...



For the NWS … Real-time use & evaluation

Joint NWS SOO–NASA SPoRT Workshop Huntsville, Alabama 11-13 July 2006 Convective (and Lightning)...

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