# Presentation: 420675

## Other Hurricanes 

**Suhung Shen****1**** (**_[Suhung.Shen@gsfc.nasa.gov](mailto:Suhung.Shen@gsfc.nasa.gov)_**)**
**J. Acker****3****, G. Leptoukh****2****, H. Rui****3****, **
**S.  Berrick****2****,  S. Kempler****2**
**1**** George Mason University**
**2**** NASA/GSFC,   ****3**** SSAI, **
**NASA/GSFC, Code 610.2, Greenbelt, MD 20771**

- Strong cyclonic surface winds of hurricanes are known to mix ocean surface waters, a process which transports subsurface waters with increased nutrient and colored dissolved organic matter (CDOM) concentrations to the surface.  Under suitable radiation and temperature conditions, a rapid phytoplankton growth response in the hurricane wake may occur, observable as an increase in surface chlorophyll *a* (chl *a*) concentration. SeaWiFS global 8-day 9km resolution data products have recently been added to the GES-DISC Interactive Online Visualization ANd aNalysis Infrastructure (Giovanni), enabling a simple method for quickly investigating chl *a* changes subsequent to hurricane passage.  We have examined 15 hurricanes over the Atlantic, Caribbean, and Gulf of Mexico for the period June-December 2005. In a number of cases, significantly increased chl *a* is observed in the 8-day data at some point along the hurricane track.  Local increases of chl *a* usually were observed only in the 8-day interval which included the date of storm passage or the subsequent 8-day period, indicating the useful aspect of increased temporal resolution for short-term event detection.

**  ****Abstract**

- 2005-08-26
- 18:45 UTCHurricane Katrina (12L) off Florida
- Sensor:
- MODIS-Aqua
- Image from Modis Rapid Response System

- 2005-08-27
- 16:20 UTCHurricane Katrina (12L) in the Gulf of MexicoSensor:
- MODIS-Terra
- Image from Modis Rapid Response System

**  ****What is Giovanni ?**

**                     ****Summary**

** ****	****http://giovanni.gsfc.nasa.gov**
-  **Giovanni** is: the **G**ES DISC **I**nteractive **O**nline **V**isualization **AN**d  a**N**alysis **I**nfrastructure, created by the Goddard Earth Sciences Data and Information Services Center (GES DISC);
-  a Web-based visualization and analysis interface that eliminates the data acquisition step entirely;
-  an analysis system which processes satellite remotely-sensed and model simulated meteorological, oceanographic, and hydrologic data sets;
-  a visualization system offering basic statistical analyses and graphical or ASCII output;
-  and a data system which handles data with differing temporal and spatial resolutions,  thus enabling both regional and global long-term climate research and short-term "special events" investigations, as well as data validations and assessments.

- From the user perspective, Giovanni is a simple web application.  Giovanni consists of HTML templates, CGI scripts and the back-end engine, such as GrADS and IDL.  Data are stored on the server machine or on one or more remote machines accessible via GrADS Data Server (GDS) and OPeNDAP.

**  ****Data Description**

- Three data sets were used in this study. They are: SeaWiFS 8-day 9-km Standard Mapped Image (SMI) products, including chl *a*  and diffuse attenuation coefficient at 490 nm (K490); 3-hourly 0.25ox0.25o TRMM precipitation (3B42 V6); and daily sea surface wind vectors from SeaWinds on QuikSCAT.  Hurricane track data were obtained from National Hurricane Center.

- 2005 was a very abnormal year in terms of the large number of tropical storms over the Atlantic ocean and Gulf of Mexico.  A total of 30 storms developed, with 15 identified as hurricanes.  Studying remotely sensed ocean color 8-day data from SeaWiFS with Giovanni, we observed significantly increased chl *a* at some point along the hurricane path of five 2005 hurricanes.  The increased values were observed either for the 8-day period including the hurricane passage, or the subsequent 8-day period.  Elevated chl *a *does not normally persist longer than two weeks. K490 values were also increased significantly at the same locations,  indicating elevated turbidity.  It is likely that strong surface winds and vorticities of hurricanes disturb the water dramatically, mixing nutrients and CDOM to the surface and suspending sediments in shallow coastal waters.  Increased nutrients will enhance local  phytoplankton populations provided other growth factors are favorable.  For hurricane Katrina and Rita, increased chl *a* may be due to transport of waters with higher chl a from coastal regions, with the signal augmented by reflection from suspended sediments. More studies, including model simulations, are needed to better understand these ocean color variations.

- TRMM 3-hourly data shows heavy precipitation on August 26 & 27 2005 near 84oW, 24oN.

- TRMM data shows that accumulated precipitation on Aug 26 & 27 exceeded 350 mm off southern Florida.

- Average chl *a* concentration for the period August 13-20 2005, before the passage of Hurricane Katrina. Black circles indicate the subsequent track of Katrina.

- Average chl *a* concentration for the period Aug. 29 – Sept. 5 2005, after the passage of Hurricane Katrina.  Elevated chl *a* was observed west of southern Florida. Black circles indicate hurricane tracks.

- Average K490 for the period Aug. 29 – Sept. 5 2005, after the passage of Hurricane Katrina.  High K490 was observed in the same location as elevated chl a values west of southern Florida.

- Surface winds from SeaWinds on QuikSCAT on Aug. 26 & 27 (ascending nodes).  (**X**) denotes the location where elevated chl *a *and K490 was increased several days later.

- Hurricane Rita (9/18-9/26) swept through the Gulf of Mexico.  Large chl *a* was observed after the passage of Rita near 26.5oN, 90.5oW. Black circles indicate hurricane tracks. (same below)

- 8-day average chl *a* before and after the passage of Hurricane Maria (9/1-9/10 2005) over the western Atlantic ocean.  Above normal chl *a* was observed along the track of Maria.

- 8-day average chl *a* before and after  the passage of Hurricane Ophelia (9/6-9/17) over the western Atlantic ocean. Increased chl *a* was observed, especially at location where Ophelia slowed down and looped around near 31.5o N, 76oW

**Single Parameter View **

**Giovanni**

**Parameter**
**Intercomparison**

**TOMS ****EP Nimbus**

**Before Passage**

**After Passage**

**Hurricane Katrina (August 23-30 2005)**

- Acker J G, Vasilkov A, Nadeau D, Kuring N (2004) Use of SeaWiFS ocean color data to estimate neritic sediment mass transport from carbonate platforms for two hurricane-forced events, CORAL REEFS 23: (1) 39-47
- Hoge F. and P. Lyon (2002) Satellite observation of chromophoric dissolved organic matter (CDOM) variability in the wake of hurricanes and typhoons, Geophys. Res. Letter, Vol. 29, No.19, 91-92

**References:**

**Other Hurricanes**

**Observing Increased Chlorophyll-a in Storm Wakes for the 2005**

**Atlantic Hurricane Season using 8-day Data Products in Giovanni**