Status of Ground Flash Fraction Retrieval Algorithm Dr. William Koshak, NASA-MSFC

1 / 14

# Status of Ground Flash Fraction Retrieval Algorithm Dr. William Koshak, NASA-MSFC

## Status of Ground Flash Fraction Retrieval Algorithm Dr. William Koshak, NASA-MSFC

- - - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - - -
##### Presentation Transcript

1. Status of Ground Flash Fraction Retrieval Algorithm Dr. William Koshak, NASA-MSFC GLM Science Meeting Huntsville, AL September 19, 2012

2. Space Shuttle Video (STS-48)

3. Algorithms Use Maximum Group Area (MGA) to retrieve Ground Flash Fraction (α)

4. GLM Observes a Mixture of CG and IC MGAs 1000 CGs 4000 ICs 5000 total + = (Observe) Retrieve characteristics about these. INVERT Three Basic Algorithms: Simple: Bayesian: Perturbation Methods:

5. The pathway to the Analytic Perturbation Method

6. MIX

7. (Actual) (Dynamic Model)

8. BASIC PERTURBATION METHOD (Vary both d and e) Find that minimizes:

9. QUASI-ANALYTIC PERTURBATION METHOD (Vary just e; d obtained analytically) So force lives in (u, v) plane

10. ANALYTIC PERTURBATION METHOD (d and e obtained analytically) Define: But: Hence: Where: Find ethat minimizes H: Substitute optimal eback into expression for H: … Quick plot of H vs. provides the solution (i.e. value of than minimizes H)

11. RETRIEVAL ERRORS Using OTD Data Using LIS Data • Sampling from population [to create climate (a, b)]: • Ng = 40,000 flashes • Nc = 120,000 flashes • Z = Nc/Ng = 3

12. Thank You (Questions?)