Literature review of the current status in the sprite observations

1. Properties of sprites2. The morphology of sprites3. Temporal evolutions of sprites4. The spectroscopy and photometry ofsprites5.Concluding remarksSDR / 9 June 2000 Science Team 2

1. properties of sprites (1)• Sprites are luminous events at altitude of 30-90kmabove large thunderstorm systems [Sentman et al.,1995; Winckler, 1995; Lyons, 1996; Suszcynsky, etal., 1998, Wesscott, et al., 1998].• Sprites are often described as an electric dischargeor breakdown at mesospheric attitudes occurringabove large positive cloud to ground (+CG) lightning.• But, not all sprites closely follow such discharge, orany recorded discharge at all.• Two evidences of sprites are closely associated withnegative cloud-to-ground (-CG) lightning strokes[Barrington-Leigh, et al., 1999].SDR / 9 June 2000 Science Team 3

First recorded sprite image :At 22:14 CST on July 6, 1989, Franz, Nemzek and Winkler recorded a twinflash originating in a storm top cloud and discharging into the stratosphere.[Franz, et al.,1990]SDR / 9 June 2000 Science Team 4

First color image of a sprite :the first color television picture of a Red Sprite, obtained in thesummer of 1994 by the University of Alaska sprites research teamfrom aboard a NASA research jet aircraft.[ Sentman et al., 1995]SDR / 9 June 2000 Science Team 5

Perez, R. and J. Michalsky, (1991): Characterization of a Direct UV Irradiance Sensor for the Evaluationof Solar Detoxification Feasibility. Report to Sandia National Labs. #788804. SNLA, Albuquerque, NM.Bailey, B., R. Stewart, J. Doty, R. Perez and W. Huse, (1991): Photovoltaic Demand-Offset System.Soltech 91, San Francisco, CA.Bailey, B., R. Stewart, J. Doty, R. Perez and W. Huse, (1991): Utility Investigation of a Grid-ConnectedPV System as a Peak Load Reduction Option. Proc. of 26th Intersociety Energy Conversion EngineeringConference.Fontoynont, M., P. Barral and R. Perez, (1991): Indoor Daylighting Frequencies Computed as a Functionof Outdoor Solar Radiation Data. Proc. of 22nd International Illumination Commission (CIE) Conference,Melbourne, Australia.Michalsky, J.J., R. Perez, L. Harrison and B.A. LeBaron, (1991): Spectral and Temperature Correction ofSilicon Photovoltaic Solar Radiation Detectors. Solar Energy 47, pp. 299-306.Vazquez, M.V. Ruiz and R. Perez, (1991): The roles of scattering, absorption and air mass on the diffuseto-globalcorrelations. Solar Energy 47, pp. 181-188.Perez, R. and M. Fontoynont, (1991): Future Directions in Daylighting Research. Australia-New ZealandArchitectural Science Assoc. Meeting, July 17-19, Roseworthy, South Australia.Published in 1992Perez, R., J. Michalsky and R. Seals, (1992): Modeling Luminance Distribution for Real Skies; evaluationof existing algorithms. Illum. Eng. Soc. Journal, Vol. 21, 2, pp. 84-92.Perez, R., P. Ineichen, E. Maxwell, R. Seals and A. Zelenka, (1992): Dynamic Global-to-Direct IrradianceConversion Models. ASHRAE Transactions-Research Series, pp. 354-369.Perez, R., R. Seals and J. Michalsky, (1992): Modeling Skylight Angular Distribution from RoutineIrradiance Measurements. Proc. IES Annual Conference, San Diego, CA.Perez, R., R. Seals and R. Stewart, (1992): Evaluation of Satellite-Based Solar Resource Assessment forInvestigating Utility Load Matching, 11th PV AR&D Review Meeting, Denver, CO.Wenger, H., T. Hoff and R. Perez (1992): Photovoltaics as a Demand Side Management Option: Benefitsof a Utility-Customer Partnership. Proc. of World Energy Engineering Congress, Atlanta, GA (10/92).Zelenka A., G. Czeplak, V. D'Agostino, W. Josefsson, E. Maxwell and R. Perez (1992): Techniques forSupplementing Solar Radiation Network Data, Final Report of International Energy Agency Solar Heatingand Cooling Program, Task 9 subtask 9D. Report IEA-SHCP-9D-1, available from Swiss MeteorologicalInstitute, Zurich, Switzerland.Published in 1993Perez, R., R. Seals and J. Michalsky, (1993): An All-Weather Model for Sky Luminance Distribution -- APreliminary Configuration and Validation. Solar Energy 50, 3, pp. 235-245.Perez, R., R. Seals, J. Michalsky and P. Ineichen, (1993): Geostatistical Properties and Modeling ofRandom Cloud Patterns for Real Skies. Solar Energy 51, 1, pp. 7-18.

2. the morphology of sprites(1)• A “carrot” sprite has a bright head region, wispy hairsextending above the head and bluish tendrils below.• An “angel” sprite also has tendrils, but the head iscapped by a diffuse glow.• “Columniform” sprites (c-sprites) has long verticalcolumn streamer about 10 km long, less than 100min diameter [Winckler, et al., 1998; Inan, et al.,1998],and show virtually no variation in brightness alonglength.• A “wishbone” sprite has a “Y” type curved streamer.Beside different from c-sprite in shape, the brightnessof wishbone sprites varies along length.SDR / 9 June 2000 Science Team 7

SDR / 9 June 2000 Science Team 8

SDR / 9 June 2000 Science Team 9

SDR / 9 June 2000 Science Team 10

SDR / 9 June 2000 Science Team 11

2. the morphology of sprites(2)• Sprites may appear in a group.• Telephoto images indicate that the carrotsprites or angel sprites are groups of c-spritesand wishbone sprites [Inan, et al., 1998,Mende, et al., 1999].• Fine structure of sprites.• Elve with sprites.SDR / 9 June 2000 Science Team 12

Sprite fireworks- Group of spritesSDR / 9 June 2000 Science Team 13

Fine structure of spritesA beady structure in the lower half of the luminous columns andwhich also is a very common feature of our recorded sprite eventsSDR / 9 June 2000 Science Team 14

Elve with Carrot Sprite(near center)SDR / 9 June 2000 Science Team 15

Elve with C-Sprite(off center)SDR / 9 June 2000 Science Team 16

3. Temporal evolutions ofsprites• Dancing sprites: a series of successivesprites that appeared to "dance" acrosshundreds of kilometers region withinhundreds of milliseconds.• Re-brightening• High-speed video of sprites show that theyare typically initiated at an altitude of about 75km and usually develop simultaneouslyupward and downward from the point of originwith an initial columniform.SDR / 9 June 2000 Science Team 17

Dancing spritesSDR / 9 June 2000 Science Team 18

Re-brighteningSDR / 9 June 2000 Science Team 19

A carrot sprite initiated at an altitude ofabout 75 km and developsimultaneously upward and downward.SDR / 9 June 2000 Science Team 20

The columns and tendrils propagateddownward in a cluster of angel andcolumniform spritesSDR / 9 June 2000 Science Team 21

4. The spectroscopy andphotometry of sprites (1)• Identify the red component as nitrogen firstpositive (N 2 1P) emission [Mende, et al.,1995;Hampton, et al., 1996].• Blue photometric measurements of thenitrogen second positive (N 2 2P) 399.8 nmand the first negative (N 2+ 1N) 427.8 nmemission from sprites are obtained[Armstrong, et al. 1998; Suszcynsky, etal.1998] — the significant ionization occursduring sprite generation.SDR / 9 June 2000 Science Team 22

Identify the red component as nitrogenfirst positive (N 2 1P) emission[Mende, et al.,1995] [Hampton, et al., 1996].SDR / 9 June 2000 Science Team 23

Blue photometric measurements ofN 2+ 1N (427.8 nm) emission from sprites.SDR / 9 June 2000 Science Team 24

4. The spectroscopy andphotometry of sprites (2)• The brightest blue images show a sustainedtendril geometry and a nearly constantintensity of emission over the entire verticalextent of the sprite [Suszcynsky, et al.1998].• The ratio of intensity of the 399.8 nmemission to that of 427.8 nm emission can beused to discriminate among sprite, elves andlightning.• Spectrum of tendrilSDR / 9 June 2000 Science Team 25

The brightest blue images show a sustainedtendril geometry and a nearly constant intensityof emission over the entire vertical extent ofthe sprite.SDR / 9 June 2000 Science Team 26

The ratio of intensity of the 399.8 nmemission to that of 427.8 nm emissionof a sprite.SDR / 9 June 2000 Science Team 27

The ratio of intensity of the 399.8 nmemission to that of 427.8 nm emissionof an elve.SDR / 9 June 2000 Science Team 28

The ratio of intensity of the 399.8 nmemission to that of 427.8 nm emissionof a normal lightning.SDR / 9 June 2000 Science Team 29

Spectrum of tendrilSDR / 9 June 2000 Science Team 30

5. Concluding Remarks (1)• A Successful theoretical model of spritegeneration needs to account for thefollowing properties of these sprites:1. Spatial properties: the richness ofmorphology, the fine structures of sprites2. Temporal properties: dancing, rebrightening,propagation of the streamers.3. Results of spectroscopic and photometricmeasurements.SDR / 9 June 2000 Science Team 31

5. Concluding Remarks (2):The dynamics and the morphologyof spritesLightninglight upthestreamersourceDownwardstreamerUpwardstreamerC-spriteDiffusing glowat higher altitude.Branching andbeady structureat lower altitude.AngelSpriteCarrotspriteHugesprites :Clustersofc-sprites,angelsprites,orcarrotsprite.WishbonespriteSDR / 9 June 2000 Science Team 32