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Research Spending & Results

Award Detail

Awardee:TEXAS A & M UNIVERSITY
Doing Business As Name:Texas A&M University
PD/PI:
  • Anthony H Knap
  • (979) 862-2323
  • tknap@geos.tamu.edu
Co-PD(s)/co-PI(s):
  • Kathryn Shamberger
  • Henry Potter
  • Steve DeMarco
  • Piers Chapman
Award Date:12/04/2017
Estimated Total Award Amount: $ 199,592
Funds Obligated to Date: $ 199,592
  • FY 2018=$199,592
Start Date:12/15/2017
End Date:11/30/2018
Transaction Type:Grant
Agency:NSF
Awarding Agency Code:4900
Funding Agency Code:4900
CFDA Number:47.050
Primary Program Source:040100 NSF RESEARCH & RELATED ACTIVIT
Award Title or Description:RAPID: The impact of increased fresh water input from Hurricane Harvey to the water quality and stratification of coastal and offshore waters of Texas.
Federal Award ID Number:1760381
DUNS ID:020271826
Parent DUNS ID:042915991
Program:PHYSICAL OCEANOGRAPHY
Program Officer:
  • Baris Uz
  • (703) 292-4557
  • bmuz@nsf.gov

Awardee Location

Street:400 Harvey Mitchell Pkwy South
City:College Station
State:TX
ZIP:77845-4375
County:College Station
Country:US
Awardee Cong. District:17

Primary Place of Performance

Organization Name:Geochemical Environmental Research Group
Street:833 Graham Rd
City:College Station
State:TX
ZIP:77840-3149
County:College Station
Country:US
Cong. District:17

Abstract at Time of Award

In late August 2017, Category 4 Hurricane Harvey made landfall on Coastal Texas, 2017 and stalled bringing 125 cm of rain to Southeastern Texas over a five-day period resulting in catastrophic flooding along most of the Gulf coast of Texas as well as the metropolitan Houston area and 18 surrounding counties. Dams and reservoirs filled and even on September 1st ? 3rd releases from these dams continued to flood the area releasing even more water. Approximately 11 trillion gallons were estimated to have fallen and eventually this freshwater will be released onto the broad Texas continental shelf. In the US alone there has never been so much fresh water impacting a coastal area other than the discharge of the Mississippi River, which divides between the Atchafalaya River and the Birdfoot Delta to the east and injects freshwater into a much narrower shelf and into much deeper water in the north-central Gulf. The main hypothesis of the Rapid response project is that freshwater from Hurricane Harvey has 1) reduced coastal water quality by increasing stratification, and thereby inhibiting ventilation of atmospheric oxygen to sub-surface waters and 2) increased respiration by transporting nutrients from terrestrially derived sources leading to increased biomass and microbial activity. Secondly, the ocean heat content of the Texas Bight region contributed to the intensification of Hurricane Harvey by supplying thermal heat to the storm as it passed from the deep Gulf of Mexico to the shelf region. This project will provide critical information on how freshwater runoff from hurricane Harvey is impacting the stratification, oxygen, nutrient budgets of the coastal waters and whether this could lead to hypoxia and other long-term ecological impacts along the Texas shelf. The data will be made available rapidly to other researchers, students and the public. This project aims to answer two questions of importance which could not be answered without a major flood. Is the freshwater from Hurricane Harvey reducing coastal water quality by increasing stratification, thereby inhibiting ventilation of atmospheric oxygen to subpycnocline water and is it increasing respiration by transporting nutrients from terrestrially derived sources leading to increased biomass and microbial activity? The project will also seek to determine if the ocean heat content of the Texas Bight region contributed to the intensification of Hurricane Harvey by supplying thermal heat to the storm as it passed from the deep Gulf of Mexico to the shelf region. This Rapid response project will conduct two research cruises on the R/V Pelican, one in late September and one in mid-November to quantify the effects and potential impacts of the freshwater run-off from Hurricane Harvey along the southern coast of Texas. In addition to the two cruises using a suite of oceanographic physio-chemical measurements, an autonomous Wave Glider will sample a grid to follow the freshwater plume and a buoyancy-controlled ocean glider will determine the depth and characteristics of the freshwater intrusion and its evolution between cruises and after data from two cruises in June and August 2017 prior to Hurricane Harvey. The research cruises will use existing offshore observing systems, i.e., the Texas Automated Buoy System, the Texas HF Radar network, and the Texas A&M University buoyancy-controlled glider program, to integrate the observations into a comprehensive picture of how the coastal region responded to the impulsive freshwater resulting from the unprecedented terrestrial flooding event in southeastern Texas.


Project Outcomes Report

Disclaimer

This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.

Texas A&M University was awarded a RAPID grant to invesigate the impact of rainfall from Hurricane Harvey. As a rapid response, we proposed two cruises on the RV Pelican to carry out an investigation of the effects and potential impacts of the freshwater run-off from Hurricane Harvey. The first cruise was completed 22nd Sept. to 1st Oct. and the second was completed 15th-20th Nov. In addition to the two cruises, a suite of oceanographic physio-chemical measurements were made. This included  the use of a Liquid Robotics SV3 Wave Glider to follow the freshwater plume, a Teledyne-Webb buoyancy glider to determine the depth and characteristics of the freshwater intrusion and its evolution between cruises, and data from two cruises in June and August 2017 prior to Hurricane Harvey. The data from the two cruises was compared to data collected in June 2017 and August 2017 prior to Hurricane Harvey?s landfall in late August 2017.

Hurricane Harvey entered the Gulf of Mexico as a tropical depression on 23 August 2017; two days later it had strengthened to a category 1 hurricane. Over the following 30 hr Harvey rapidly intensified, reaching the Texas Bight as a category 3 storm. This intensification continued while Harvey crossed the shelf, making landfall as a category 4 storm 60 km east of Corpus Christi, TX on 26 August. A hydrographic survey two weeks prior to landfall shows that the tropical cyclone heat potential across the Texas Bight was approximately 35 kJ/cm2, which is 55 kJ/cm2 less than the amount of upper ocean heat normally associated  with intensification. Combined with buoy, float, and satellite data, we use hydrographic surveys to study the conditions of the Texas Bight that contributed to Harvey's rapid intensification.

Hurricanes rely on heat extracted from the upper ocean as their energy source. When the ocean is warm conditions are more favorable and hurricanes are often stronger.  Hurricanes also mix the ocean which brings cold water from greater depth and can lead to intensity reduction. Tropical cyclone heat potential is a measure of heat in the upper ocean which is available as an energy source for hurricanes.

In shallow water tropical cyclone heat potential is typically low because there is not as much water to store heat; therefore, hurricanes are not expected to intensify over shallow water. we show that hurricane Harvey did intensify over the shallow water off the Texas coast despite having low heat potential. Using ocean measurements, we found that the reason was because the ocean was very warm from the surface to the seabed. Therefore, when Harvey mixed the ocean very little cold water was brought up from below and the surface remained warm which allowed Harvey to continue to strengthen. Results suggest that tropical cyclone heat potential is ineffective for estimating hurricane strength in shallow water and demonstrates the importance of knowing subsurface temperatures if we want to improve hurricane forecasts.

The two cruises provided opportunities for a considerable number of graduate and undergraduate students to experience research at sea. The September cruise provided space for 15 MS and PhD students, 7 undergraduates, and 3 post-docs on the three legs. The November cruise had only one leg, and accommodated 4 graduates and 4 undergraduates.  A graduate student was co-chief scientist during leg 1 of the September cruise, with junior faculty acting as chief and co-chief scientists during legs 2 and 3. The chief scientist for the November cruise was a junior research scientist. Several graduate students collected samples for their own research during each cruise, while undergraduates acted as watch keepers and learned how to sample for multiple parameters under the supervision of experienced seagoing researchers. 

These RAPID Awards by NSF provide incredible opportunites to conduct science when a disaster strikes. Science benefits greatly from this program.  

 

 


Last Modified: 04/13/2019
Modified by: Anthony H Knap

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