Hurricane and Severe Storm Sentinel (HS3) 2014: Third Flight over Hurricane Gonzalo Completed

October 19th, 2014 by Mary Morris
The WB-57 prepares for takeoff on Friday, October 17th, 2014 from MacDill Air Force Base.

The WB-57 prepares for takeoff on Friday, October 17th, 2014 from MacDill Air Force Base.

On Friday morning, at 7:40 AM EDT, our WB-57 took off for a third, and final flight over Hurricane Gonzalo. At the time of our flight, Gonzalo was a Category 3 storm located south of Bermuda. While we were flying Gonzalo, one of the NOAA P-3s was also investigating Gonzalo. The data the P-3 collected will be particularly useful for the WB-57 instrument teams to validate our results. For example, HIRad is very similar to the Stepped Frequency Microwave Radiometer (SFMR) onboard the NOAA P-3. We can use SFMR data that is collocated with HIRad data to validate our results over the coming weeks.

Members of the instrument teams wait for the WB-57 to taxi back to the hangar after the third science flight over Hurricane Gonzalo.

Members of the instrument teams wait for the WB-57 to taxi back to the hangar after the third science flight over Hurricane Gonzalo.

We still have through the end of October for science flights, so the forecasting team is looking for the next target we can fly over. The National Hurricane Center has given a disturbance in the Gulf of Mexico, related to Tropical Storm Trudy, a medium chance of tropical cyclone formation in the next five days. There is still a lot of uncertainty in the forecast, but it’s worth keeping an eye on the Gulf next week. We always stay prepared for flights on the off chance that something turns out to be a better target for us than originally forecast. Stay tuned!

The folks at the NOAA aircraft operations center were kind enough to share some space with us for the few days we were based out of MacDill. Here, I am, exhilarated after three long, but successful, days of science flights.

The folks at the NOAA aircraft operations center were kind enough to share some space with us for the few days we were based out of MacDill. Here, I am, exhilarated after three long, but successful, days of science flights.

Hurricane and Severe Storm Sentinel (HS3) 2014: Hurricane Gonzalo: The Hunt for Data Continues

October 16th, 2014 by Mary Morris
The WB-57 crews and pilots prepare for take-off from MacDill Air Force Base on October 16, 2014

The WB-57 crews and pilots prepare for take-off from MacDill Air Force Base on October 16, 2014

Today was another interesting day here at MacDill. Our WB-57 took off around 11:16 EDT for Hurricane Gonzalo. During the science flight, Gonzalo’s maximum sustained winds were 145 mph as it continued on its track towards Bermuda. During the ~6 hour mission we were able to cross over the eye three times.

Based on satellite imagery, it looks like the flight planners did a good job at nailing the eye crossings. The team here spends a lot of time planning out coordinates in advance in order to create flight tracks that will give us the best view of the storm. It’s not as simple as just forecasting the center position of the hurricane because we also have to consider the other parts of the hurricane environment that we want to study. All the instrument teams have preferences for the types of data they want to get, but in the end we need to compromise and find a track that works for everyone.  Today’s track put us in a good position to look at the inner core of the storm as well as upper level outflow. We cannot wait to get a look at the processed data to see how well the flight track worked out.

Sitting under the WB-57, I hide from the hot Florida sun and download HIRad data from today’s flight.

Sitting under the WB-57, I hide from the hot Florida sun and download HIRad data from today’s flight.

The plan for tomorrow is to get one last flight over Hurricane Gonzalo, but we’ll have to get an early start, taking off at 7am, in order to make the most out of the WB-57’s range. Due to range limitations, we will probably only get two passes over the eye this time, but it’s better than nothing. After tomorrow’s flight, the researchers will head back to their respective homes until we find a new suitable target to fly over.

After a second successful flight over Hurricane Gonzalo, crews prepare the WB-57 for the next flight from MacDill Air Force Base.

After a second successful flight over Hurricane Gonzalo, crews prepare the WB-57 for the next flight from MacDill Air Force Base.

Hurricane and Severe Storm Sentinel (HS3) 2014: Science Flights over Hurricane Gonzalo Begin

October 15th, 2014 by Mary Morris
Maintenance crews and the pilots prepare for departure from MacDill Air Force base on October 15, 2015

Maintenance crews and the pilots prepare for departure from MacDill Air Force base on October 15, 2015

HS3 UAV flights officially ended a couple of weeks ago, but there has been a successful extension of the HS3 mission through a new NASA/Navy collaboration. Two instruments from HS3 that didn’t get to fly this hurricane season due to aircraft issues, HIRad and HIWRAP, are now loaded onto a manned WB-57 and will be flying over storms through the end of October.

Members of the team collaborate as they launch dropsondes into Hurricane Gonzalo during a science flight on October 15, 2014

Members of the team collaborate as they launch dropsondes into Hurricane Gonzalo during a science flight on October 15, 2014

Things are looking up for the HIRad and HIWRAP teams, as we just finished our first successful science flight over Hurricane Gonzalo today. Hurricane Gonzalo is undergoing an eyewall replacement cycle and has a maximum sustained wind of 125 miles per hour. Headed towards Bermuda, Gonzalo is expected to maintain its major hurricane status through Friday. Luckily, Gonzalo is in range of the WB-57, which will be based out of the MacDill Air Force base in Tampa, FL through Friday. The team here is working hard to get as much data as possible. Stay tuned!

The WB-57 lands after completing its first science flight at MacDill Air Force base on October 15, 2015

The WB-57 lands after completing its first science flight at MacDill Air Force base on October 15, 2015

 

NASA in Alaska 2014: More Flying with ARISE

October 8th, 2014 by Michal Segal Rozenhaimer

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Editor’s note: The following is a first-hand account of ARISE survey flights by one of the mission’s researchers. To see the first two days’ accounts, visit:
http://earthobservatory.nasa.gov/blogs/fromthefield/2014/09/17/flying-with-arise/

Day 3 (Sept. 16, 2014)

Today was a long flight day. It started off by trying to guess where the high clouds (i.e. cirrus) will move in. We had to choose between three options, and our choice turned out to be a good bet. We flew to the edge of the sea ice to try to characterize both its exact mapping and see whether the clouds look different or have different characteristics, height and composition (i.e. water and ice) above the sea-ice versus open ocean. We had a mix of high clouds above ice but also clear regions, with black and white ice, as seen in the pictures. The sun was posing for us and we got to see some halo forming around the sun. This means that we had ice clouds (cirrostratus) with particular ice shapes of smooth hexagonal crystals are reflecting and refracting the sun rays to form this circle of light surrounding the sun.

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Day 4 (Sept. 18, 2014)

Today was a challenging day. We were after clouds, and oh, they are “hard-to-get” into a specific posture. We flew high to check the area and had a gorgeous stratus deck below us. The word stratus in Latin means “spread out” and boy, they were spread out all right.

At some point we saw an opportunity to dive below the clouds,  and cruising over the broken sea-ice, we felt like we were in a Star Trek episode.

Clouds are so diverse and changeable, so we want to sample them as often as possible to get a feel for their heights, thicknesses and what type of particles they include (water, ice or a mixture of both). This is important because their location in the atmosphere (how high or low they are) and their composition dictates the amount of radiation they absorb or scatter back into space and how they affect the surface below, either warming or cooling. This was a challenging and bumpy flight from all perspectives, but all in all it ended well.

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Summary

We had many more flights, some I flew myself, some were flown by my 4STAR team fellows. All flights were magnificent in that they covered pristine sea ice regions, where human access is difficult and low and high clouds over these regions (especially at this time of year) means even the satellites often cannot take measurements. We had some weather and technical hurdles some days, but we succeeded in most of our goals, which were to measure sea-ice formation and state, study sunlight and thermal energy over the sea-ice and open ocean, and characterize cloud spread and type in this complex and important region.

Our final science flight was on Oct. 2, and was dedicated to instrument calibration. It lasted for almost nine hours and ended after sunset, since some of the instruments (including our own SUN-photometer) needed to be calibrated by the sun, looking at the wide range of sunlight intensity during sunrise or sunset period. We flew over some dormant volcanos in the southern part of Alaska, over glaciers and Denali park. What a great finale to a great campaign! Looking forward for next year’s one already.

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LARGE (The Langley Aerosol Research Group Experiment) 2014: Aerosols around Hurricane Edouard

October 6th, 2014 by Luke Ziemba

Most of the North American population probably wasn’t paying much attention, but the largest Atlantic storm since SANDY safely passed by the mainland well East of Bermuda in Mid-September.  Edouard reached ‘Major Hurricane’ status as a category-3 storm on 9/16 and weakened over colder waters several days later.  Below is a track for Edouard, compared to the three other hurricanes of the 2014 season.

2014 season, courtesy of http://www.nhc.noaa.gov/data/tcr/index.php?season=2014&basin=atl

2014 season, courtesy of http://www.nhc.noaa.gov/data/tcr/index.php?season=2014&basin=atl

Edouard presented an excellent opportunity to assess several outstanding aerosol-related objectives for our group.  First, the spatial distribution of particles throughout hurricane regions is largely unknown.  Satellites can observe aerosols on the periphery of storms in clear regions, but the presence of clouds make these measurements impossible.  Thus, in-situ observations are essential to see if particles can survive transport towards the eye of the storms.   In general, we encountered much more clear air during storm transects at 10,000 ft altitude than I was expecting, and aerosol concentrations were highly variable from very clean (10-s of particles/cm3) to 1,000 particles/cm3.  Future analysis will aim at better understanding this variability.

Another objective of our project is to observe and explain high concentrations of particles inside hurricane eyes.  During Edouard, we consistently observed significantly enhanced particle number concentrations (up to 7,000 particles/cm3) and cloud condensation nuclei (CCN) in the clear, well-defined eye region.  While these concentrations do not compare with polluted urban/continental regions, they may play a significant role for hurricane intensity by seeding the eyewall and potentially strengthening the storm.  We hope to continue sampling storms like Edouard to understand where and under what environmental conditions these particles are formed.

The unique conditions encountered inside the eye of a hurricane are pretty amazing, but also may directly lead to formation of the aerosols we sampled.  For each of the 8 penetrations we made through the eye (on 3 flights), very few clouds were present resulting in sunlight penetrating all the way down to the fairly calm ocean water.  Air in the eye is slowly subsiding from aloft and is clean and cool.  New particle formation and growth typically requires these exact conditions; light to promote photochemical reactions, minimal surface area for gases to condense, colder temperatures, and enough time for growth to relevant sizes.  Below are a few pictures from inside the eye.

Edouard Eyewall on 9/16

Edouard Eyewall on 9/16

calm ocean surface in Edouard Eye, 9/15

Calm ocean surface in Edouard Eye from 10,000 ft, 9/15

Other scientists on these flights were also taking advantage of this large well-defined eye to test newly developed unmanned aircraft, which can be used to fly in regions of the hurricane that are unsafe for manned aircraft. The link below contains a story and video about the NOAA ‘coyote':

http://www.weather.com/news/science/edouard-noaa-drones-20140920

Next up for LARGE will be sampling from Fairbanks, AK for the ARCTIC FLUX campaign.  While we don’t expect to see hurricanes, this region has interesting aerosol characteristics that offer more exciting scientific opportunities…

Notes from the Field