1 / 12

Longwave Cloud Forcing Due to Tropical Cyclone Presence: August 1995

Longwave Cloud Forcing Due to Tropical Cyclone Presence: August 1995. Cristy King. What I want to know. If tropical cyclone (tropical depression, tropical storm, and hurricane) cloud cover affects the outgoing longwave radiation. Data.

nadine-beasley
Download Presentation

Longwave Cloud Forcing Due to Tropical Cyclone Presence: August 1995

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Longwave Cloud Forcing Due to Tropical Cyclone Presence: August 1995 Cristy King

  2. What I want to know • If tropical cyclone (tropical depression, tropical storm, and hurricane) cloud cover affects the outgoing longwave radiation

  3. Data • NOAA Interpolated Outgoing Longwave Radiation at TOA from the NOAA14 satellite • Spatial Coverage: 2.5 X 2.5 degree grid

  4. Data Continued • Spatial: • Tropical Atlantic • 75W to 20W • 10N to 30N • Temporal: • Daily OLR • August 22, 1995 to August 31,1995 • 4 cyclones present

  5. Storm Tracks • 8 Humberto • 9 Iris • 11 Karen • 12 Luis

  6. August 27,1995 • Anomalous OLR

  7. Threshold • Hartmann et al. 2001 used a threshold of 30 W/m^2 • Test statistic revealed at 95% confidence level a range of -28 < mean < +28 • Threshold=30 W/m^2 96.4% of longterm mean OLR lie between 220 – 280 with a mean value of 260 W/M^2

  8. In any direction about the core of the cyclone, TOA OLR increases By offsetting the above OLR values by 30 (the threshold) we obtain the LWCRF due to the presence of the cyclone

  9. Distribution of OLR about the core

  10. Of total LWCRF: • 37% comes from within a radius of 1 grid box (242km) • 65% comes from within a radius of 2 grid boxes(484km) • 82% comes from within a radius of 3 grid boxes(726km)

  11. Correlation • TOA OLR w/ Storm Category = -.15 • TD=1 TD/TS= 1.5 TS=2 TS/H=2.5 H=3 • TOA OLR w/ SST = .23 This is expected because if correlation w/ SST was strong, we would conclude that there is no net LWCRF induced by the cyclone

  12. Conclusions/Comments • Tropical cyclone cloud cover does significantly affect the outgoing longwave radiation • Similar results were found for all 4 storms • SWCRF may balance the LWCRF leading to a NET CRF close to 0 but SW values are needed on a daily timescale as opposed to monthly • Contours of monthly OLR washed out much of the signal

More Related