Ten years ago, Hurricane Katrina devastated New Orleans and the Gulf Coast. Since then, scientists have made a decade’s worth of advances in hurricane simulation technology hoping to save lives in years to come. One of these advancements allows for a hauntingly clear look back in time at Katrina, one of the five deadliest hurricanes in recorded US history.
Bill Putman at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, published video footage of a simulation of Hurricane Katrina on Friday. This video, created in 2015, takes a combination of Hurricane Katrina observational data recorded every six hours by NASA’s high-resolution global model (GEOS-5) to produce a global simulation of the storm. The advances today allow for a horizontal resolution of approximately four miles for the storm’s development period and path in August, 2005, a much greater resolution than that available by 2005 standards. Thanks to what Putman calls “higher resolution models with improved representation of physical processes, advanced data assimilation techniques, and better supercomputers,” simulations in 2015 can recreate historical storms in intricate detail to help researchers study past events, learn from them, and improve on warnings for residents in the path of a dangerous hurricane.
Putman describes the incredible footage of the historical Katrina simulation in his YouTube post.
“In this video… the depression that becomes Katrina drifts north of Hispaniola becoming a tropical storm over the Bahamas on the 24th of August. The right panel shows water vapor, and the left shows wind speeds near the surface. After crossing the southern tip of Florida as a minimal hurricane, Katrina rapidly intensified to a Category 5 hurricane over the warm waters of the Gulf of Mexico from the 26th to the 28th. During this period of intensification, a strong core of intense winds surrounds the compact eye of Katrina while bands of moisture feeding into the circulation can be seen in the water vapor images. Katrina makes landfall along the coast of Louisiana on August 29th as a Category 3 hurricane with wind speeds in excess of 120 mph. The moist low-lying geography of the lower Mississippi valley into New Orleans do little to weaken the strength of Katrina’s winds as it moves north making a final landfall near the Louisiana/Mississippi border. Advances in science and computing allow modern global models to represent all aspects of Katrina’s life cycle. These advances have lead to substantial improvements in forecasts of hurricane landfall and intensity.”
Storm models from 2005 were only able to provide a 50 km resolution for a hurricane like Katrina, whereas current hurricane models have defined clarity of resolution to 6 km, as per Quartz. According to Buffalo station WKBW, this is due, in part, to the replacements and upgrades NASA has made to precipitation satellites. The higher clarity is also partially due to increased manned and unmanned flights within the Earth’s atmosphere.
“It used to be that we always looked for the mechanisms that allow hurricanes to rapidly intensify, but as of late, the question has gotten flipped around,” said research meteorologist Scott Braun to Quartz. “Now we ask what are the factors that prevent a hurricane from intensifying.”
Braun added that high wind shear, or “a large change in winds with height, in the storm’s environment,” is one of the factors that prevents a hurricane from gathering strength.
NASA teams have been producing models with ever-increasing resolutions. Improving resolution has been a goal for scientists hoping to better hurricane forecasts. It is the ability to ingest the data, a.k.a. the “data assimilation procedure,” according to NASA, that is key. Vast improvements have been made in the number of instruments made available to collect that data. NASA’s Earth Observing System (EOS) now maintains roughly a dozen active satellites that are honed in to study weather and climate. In the past nine years, six new satellites have been launched, including CloudSat, NASA-NOAA’s Suomi NPP satellite, Aqua, Terra and CALIPSO. Devices to study hurricane formation are employed on these satellites as well as a fleet of other spacecraft, including the Global Precipitation Measurement core observatory.
In 2016, NASA plans to launch the Cyclone Global Navigation Satellite System, a “constellation of eight small satellites.” CYGNSS will probe the inner core of a hurricane in greater detail to help scientists determine the process behind the rapid intensification of a system like Katrina. NASA hopes that CYGNSS will provide more frequent measurements within storms. This will allow CYGNSS to transmit “accurate measurements of ocean surface winds both in and near the eye of the storm” throughout the life cycle of a tropical hurricane. The goal for the satellite system is to vastly improve hurricane intensity forecasts.
“There are typically multiple instruments on every spacecraft with various purposes that often complement each other,” said Eric Moyer, the Earth science operations manager at NASA Goddard. “We can see the progression of a storm from one day to the next using the Terra and Aqua satellites—a morning and afternoon view of every storm system, every day.”
As reported by Time Magazine, Katrina made landfall in southeast Louisiana as a Category 3 storm on August 29, 2005, at 6 a.m. Packing sustained winds of 100-140 mph, the hurricane stretched over 400 miles across, as recorded by the History Channel. The hurricane and its aftermath took the lives of 1,833 people. Katrina destroyed over 100,000 homes in New Orleans alone. Nearly 80 percent of the Crescent City flooded.
Propagated by these devastating numbers, researchers strive to better their understanding of hurricane development. The decade since Katrina has proven relatively mild in hurricane terms. Since 2005, there hasn’t been a single hurricane stronger than category 2 to make landfall in the U.S. This is a mild climatological period NASA experts claim only happens roughly every two centuries.
[Image by NASA]