The 13 years of TRMM Lightning Imaging Sensor: The 13 years of TRMM - - PowerPoint PPT Presentation

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The 13 years of TRMM Lightning Imaging Sensor: The 13 years of TRMM Lightning Imaging Sensor: From individual flash characteristics to decadal tendencies From individual flash characteristics to decadal tendencies 1,2 , S. J. Goodman 3 , W. A.

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SLIDE 1

The 13 years of TRMM Lightning Imaging Sensor: The 13 years of TRMM Lightning Imaging Sensor:

From individual flash characteristics to decadal tendencies From individual flash characteristics to decadal tendencies

  • R. I. Albrecht
  • R. I. Albrecht1,2

1,2, S. J. Goodman

, S. J. Goodman3

3, W. A. Petersen

, W. A. Petersen4

4, D. E. Buechler

, D. E. Buechler5

5,

,

  • E. C. Bruning
  • E. C. Bruning6

6, R. J. Blakeslee

, R. J. Blakeslee4

4, H. J. Christian

, H. J. Christian5

5 1 1 Instituto Nacional de Pesquisas Espaciais (INPE/CPTEC)

Instituto Nacional de Pesquisas Espaciais (INPE/CPTEC)

2 2 Cooperative Institute for Climate and Satellites (CICS/UMD)

Cooperative Institute for Climate and Satellites (CICS/UMD)

3 3 National Oceanic and Atmospheric Administration (NOAA/NESDIS/GSFC)

National Oceanic and Atmospheric Administration (NOAA/NESDIS/GSFC)

4 4 NASA Marshall Space Flight Center (NASA/MSFC)

NASA Marshall Space Flight Center (NASA/MSFC)

5 5 University of Alabama-Huntsville (UAH)

University of Alabama-Huntsville (UAH)

6 6 Texas Tech University (TTU)

Texas Tech University (TTU)

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SLIDE 2

Introduction

The Tropical Rainfall Measuring Mission (TRMM) satellite was launch in November 1997. The TRMM Lightning Imaging Sensor (LIS) is a CCD array that detects lightning events at ~4.3 km of resolution during 92 seconds at nadir:

– This short sampling time during the satellite overpass requires several years to compute high resolution climatology.

Nowadays, LIS has collected lightning measurements for over 13 years which enable us:

– To make compilation of a total lightning climatology maps in high resolution such as 0.25o and 0.10o of horizontal resolution. – To infer total lightning trends over the last decade.

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SLIDE 3

Methodology

Each LIS orbit was tracked over the surface of the Tropics (±35

  • f latitude):

– in 0.50

  • , 0.25
  • and 0.10
  • grids

– computing the view time and the number of flashes at each pixel during each orbit passage. – flash count at each pixel was corrected by the instrument flash detection efficiency according to the pixel’s local standard time (LST) [Boccippio et al., 2002]

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SLIDE 4

Methodology

Flash rate density (FRD – fl km

  • 2 yr
  • 1) was calculated for the 13

year and here we analyze: 1) The climatological total lightning map and its maximums 2) Individual flash characteristics in respect to precipitation type 3) Decadal trends

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SLIDE 5

Results

1) The climatological total lightning map 1) The climatological total lightning map and its maximums and its maximums

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SLIDE 6

Results

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums fl km-2 yr-1

Christian et al. [2003] LIS+OTD 0.50o, 1995-2000

LIS 0.25o, 1998-2010 LIS 0.10o, 1998-2010

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SLIDE 7

1st maximum in Christian et al. [2003] (0.50o resolution):

– Kamembe, Rwanda: 82.7 fl km-2 yr-1, with 221 thunderstorm days per year.

1st maximum in LIS 0.25o and 0.10o (1998-2010):

– Lake Maracaibo, Venezuela: 250 fl km-2 yr-1, with 333 thunderstorm days per year

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums

fl km-2 yr-1

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SLIDE 8

– Nocturnal maximum due to a convergence of breezes over a warm lake:

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums

  • Minimum mean lake water temperature of 28.7oC
  • Mountain-valley breeze
  • Lake breeze
  • Sea breeze
  • Easterlies

fl km-2 yr-1

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SLIDE 9

– Nocturnal maximum due to a convergence of breezes over a warm lake:

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums

  • Minimum mean lake water temperature of 28.7oC
  • Mountain-valley breeze

Mountain-valley breeze

  • Lake breeze
  • Sea breeze
  • Easterlies

fl km-2 yr-1

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SLIDE 10

– Nocturnal maximum due to a convergence of breezes over a warm lake:

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums

  • Minimum mean lake water temperature of 28.7oC
  • Mountain-valley breeze

Mountain-valley breeze

  • Lake breeze

Lake breeze

  • Sea breeze
  • Easterlies

fl km-2 yr-1

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SLIDE 11

– Nocturnal maximum due to a convergence of breezes over a warm lake:

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums

  • Minimum mean lake water temperature of 28.7oC
  • Mountain-valley breeze

Mountain-valley breeze

  • Lake breeze

Lake breeze

  • Sea breeze

Sea breeze

  • Easterlies

fl km-2 yr-1

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SLIDE 12

– Nocturnal maximum due to a convergence of breezes over a warm lake:

1) The climatological total lightning map and its maximums 1) The climatological total lightning map and its maximums

  • Minimum mean lake water temperature of 28.7oC
  • Mountain-valley breeze

Mountain-valley breeze

  • Lake breeze

Lake breeze

  • Sea breeze

Sea breeze

  • Easterlies

Easterlies

fl km-2 yr-1

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SLIDE 13

Results

2) Individual flash characteristics in 2) Individual flash characteristics in respect to precipitation type respect to precipitation type

(please see the proceedings for details)

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SLIDE 14

Results

3) Decadal trends 3) Decadal trends

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SLIDE 15

Results

Flashes from LIS orbit dataset at 0.5

  • resolution:

– Post-boost orbits field of view were corrected by the pre- boost swath and LIS detection efficiency; – Cummulated daily flashes and viewtimes using a 49-day moving window to capture a full diurnal cycle (Boccippio et at., 2000); – Cummulated flash rate density pentads (5-days).

Quantile linear regression calculated for Regional Boxes:

3) Decadal trends: 3) Decadal trends:

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SLIDE 16

Results

Quantile linear regression: Quantile linear regression:

– Method to estimate the change (trend) of flash rate density (FRD) quantiles as a function of the year; – A quantile is a point taken from the inverse cumulative distribution function of the FRD so that, for examples, the 0.7 quantile is the value such that 70% of the pentad FRD have FRD below this value (70th percentile); – The coefficients βk(τ) are estimated for 19 different quantiles (τ=0.05,0.10,...,0.95) using each time the entire dataset of a regional box.

3) Decadal trends: 3) Decadal trends: y t=0t∑k=1

K

k x tkt Q∣x t1,..., x tk=0 Qy t∣x t1,... ,x tk=0∑k =1

K

k xtk

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SLIDE 17

Results

3) Decadal trends: 3) Decadal trends:

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SLIDE 18

Results

3) Decadal trends: 3) Decadal trends:

  • 2.5 (fl km-2) per year

@ Q(0.90) = 41.9 fl km-2

  • 6% per year

OLS → -0.4 fl km-2

All quantile trends are significant at 10% level

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SLIDE 19

Results

Summary for Q(0.95):

– Circles = Land trend (or No Mask) – Triangles = Ocean trend

  • Blue = negative trend on the 95

th percentile

  • Red = positive trend on the 95

th percentile

– only trends with 95% confidence are shown.

3) Decadal trends: 3) Decadal trends:

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SLIDE 20

Results – 13-years is a very small period be considered a climate trend. – But, if if it is a sign of global warming global warming, how can we explain a decrease in the high flash rate densities?

  • Convective mass flux and T relationship (Betts 1998;

Held et al., 2006; Vecchi and Soden 2007):

M c M c =P P −0.07T

∆T

Convective mass flux 3) Decadal trends: 3) Decadal trends: updraft lightning

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SLIDE 21

Thank you!

(rachel.albrecht@cptec.inpe.br)