Monthly Archives: July 2012

SARP 2012 in the Field: Central Valley Oil Fields

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By Greg Hartt, SARP Mentor

On July 3rd, the WAS (Whole Air Sampler) Group took off for the sunny San Joaquin Valley in central California to start our ground sampling trip in the oil fields near Bakersfield, CA. With an early 6:00 am start, nearly everyone spent the entire 2.5 hour van ride on the I-5 catching up on some sleep after spending the previous day in lab.

Our goal was to map the hydrocarbon emissions of the oil infrastructure in the Buena Vista, Elk Hills, and Midway-Sunset oil fields to compare with our flight data from the P-3B. In previous SARP years, our lab has focused on the emissions from dairy farms in the Central Valley, so we wondered what effect the oil fields were having on the air quality in the southern parts of the Valley. While I had done some field work around the oil fields in the spring it always seems like an adventure taking air samples up there.


Midway-Sunset and Buena Vista oil fields.

After getting off of I-5 and taking the requisite bathroom break, we started our air sampling in an agricultural area. We went over sampling technique – hold the canister up high, position yourself downwind of the canister, open slowly to allow a constant flow of air over ~30 seconds. After everyone knew what to do, we started our sampling expedition. Kelvin acted as our designated bookkeeper, recording all of the locations, times, temperatures, wind directions, etc. Ricky served as a navigator, helping move from sample site to sample site, and everyone else shared the sampling and measurement jobs throughout the day.


 Early on, we encountered a dog named Albie, who was excited to make nine new friends. Unfortunately, we had to leave him behind.

After the group warmed up with some samples off of CA-119, we took the van on some dirt roads to take samples downwind of the Elk Hills oil field. Fortunately, everyone’s stomach handled the half hour of bumpy driving – I would expect nothing less after they all fared so well on the P-3B flights.


Tamara takes an air sample near oil wells near the road.

Returning from our washboard road experience, we continued south to head through the Buena Vista oil field to begin our air sampling in the Midway-Sunset oil field, north of Taft, CA. When I started sampling in this area in February, I was astonished by the density of oil wells in this area. I was clearly not alone when the SARP students started gasping as we rounded a corner to see the Midway-Sunset oil field.


Midway-Sunset oil field.

After taking another 15 air samples in the heat, it was time for a break, so we pulled the van over next to an aqueduct north of Midway-Sunset. We all enjoyed the rest and our late-afternoon lunches, but it was soon time to move on to the next sample site in the middle of the Elk Hills oil field.

We finished off the afternoon by taking some samples among the dairies and orchards to determine the inflow from upwind locations. Finally, after eight hours of sampling in and around the oil fields, it was time to return home. Slogging through the rush hour traffic in LA, most people napped after a long day in the field, getting ready to start analyzing the samples the next morning.


Map of our sample site locations (blue dots) and the P-3B flight track (white line)

SARP 2012 in the Field: Delano Vineyards

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By Shane Grigsby, SARP Mentor


Tuesday, June 26th

Tuesday was our first day in Delano, the town closest to our field study area. We drove in from Palmdale, a trip that took us past the Mojave Desert and over the southern foothills of the Sierra Nevadas. Our destination, Delano, is a small, unassuming agricultural town of about 30,000 residents located in the central Joaquin Valley. The town is best known as the setting for John Steinbeck’s ‘Grapes of Wrath’.



Figure 1.1: Kate Garner admires the vineyard at our field site in Delano


Upon arrival, we checked into the Liberty Best Western Inn and headed to our field site. Our field site consisted of two blocks of vineyard owned by Delano Farms, one of which was subjected to water stress (half irrigation for 7-10 days), while the second block served as the control. The field site is part of a multiple-year water stress experiment run by Dr. Ustin’s colleague Dr. Smart, of the Department of Viticulture at UC-Davis. Once at the field site, Dr. Smart explained the history of the area, the nature of the experiment, how water stress is measured, and the larger impacts of water management to the state of California. In addition to meeting with Dr. Smart and his research group, we met with Dr. Ustin’s CSTARS group and discussed our sampling methodology for the following two days.

Wednesday, June 27th
Wednesday was our flight day. Some of the measurements for the experiment, such as Leaf Area Index (LAI), had some flexibility for the sampling window as they didn’t change much over small timescales. However, some of our measurements, such as water stress and water content, either follow diurnal cycles or change significantly over a few hours. To account for this, on Wednesday we took both imagery calibration measurements and in-situ field measurements for a variety of fast-changing field parameters.


Figure 1.2: From left (standing): Tao Cheng, Shane Grigsby, Dr. Alsina-Marti (Mimar), Professor David Smart, and Austin Hopkins. Kate Garner and David Buckley are in the foreground. Professor Smart discusses agriculture, water management and plant stress.


Figure 1.3: From left: Susan Ustin, Michael Whiting, Tao Cheng and John Gajardo discuss field methods and sampling techniques


Figure 1.4: David Buckley demonstrates proper all day-field attire: light-colored long-sleeve cotton shirt, wide-brimmed hat, and sunglasses



Figure 1.5: Kate Garner uses a radiometer gun for thermal calibration

Tao Cheng demonstrated many of the measurements needed for imagery calibration, including field spectral measurements with the ASD spectrometer, thermal measurements with the radiometer gun, and how to set up Spectralon panels.


Figure 1.6: Chris Goyne is outfitted by Tao Cheng with ASD field spectrometer

For the water stress parameters, we sampled leaves for both water content and water stress. Ideally, we wanted the measurements to be as close to the flyover time as possible, so we formed several small groups to bag leaves simultaneously. The leaves for water content were picked in sets of three per vine, from nine vines per sample site, at twelve different sample sites. Water stress was measured using two ‘pressure bomb’ systems, which determined the amount of pressure needed to force water out of the leaf through the stem. We took each measurement twice to align with the MASTER overflights, once in the morning and again in the afternoon.

After the fieldwork concluded, we met at our lab, which is based at Liberty Best Western Inn. At the lab, we took additional spectral measurements and first estimates for leaf area and water content from our leaf samples. Additionally, we calculated the hemispherical transmittance and reflectance with an integrating sphere provided by Dr. Ustin’s group. This allowed us to solve for absorption. We completed lab analysis by determining leaf area with a LiCor table.


Figure 1.7: Mimar explains the pressure bomb operation to Chris Goyne


Figure 1.8: The P-3 flying one of our data acquisition flight lines


Figure 1.9: Kate Garner explains the LiCor scanning system to Peter Eckert; leaf samples awaiting processing are visible under the trash bags in the foreground

We ended the day by reviewing the set-up procedure for the LiDAR system in preparation for the next day’s work, and commemorating our efforts with a group LiDAR ‘photo’.

Thursday, June 28th

For our final day of sampling we primarily examined LAI, which is used as a proxy for plant productivity. We initiated the fieldwork with an explanation of surveying techniques, a demonstration of how to set up tribrechs, and exercises in taking differential GPS points.


Figure 1.10: Aleeza and Kate cut leaves in preparation for the LiCor scanner, which requires flat leaf samples for analysis



Figure 1.11: Anthony controls the scanning rate for the LAI assessments


Figure 1.12: Mimar and Peter Eckert move one of the Flux Towers, which is used to collect data on the surface energy budget


Figure 1.13: The first scanning position with the scanner elevated above the canopy


Figure 1.14: Shane Grigsby explains survey techniques for GPS setup

We set up reflectors for the LiDAR scans and separated into groups to take measurements. Dr. Smart and Mimar supervised the students for a second day of water stress measurements, while Dr. Ustin’s research group collected reference LAI measurements. As we had sampled leaves on Wednesday and calculated out leaf area, on Thursday we collected full cane samples. This was accomplished by selecting a vine, from which several full canes were removed to obtain leaf number and cane number counts.


Figure 1.15: Reflectors arranged for linking together multiple LiDAR scans

To acquire canopy structure, leaf estimates, and leaf angles, we scanned a transect between the two data blocks. In order to take these measurements, we needed to get the equipment above the canopy–an endeavor that required some teamwork to get equipment on top of a Smart lab truck.


Figure 1.16: Shane, Austin and John set up the LiDAR scanner


Figure 1.17: Shane and Austin work with the scanner in darkness to reduce glare on the data laptop


SARP 2012 Week 2: Students fly on the NASA P-3B

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Monday:
The second week of SARP began bright and early with a 5:40AM departure from the hotel for the Dryden Aircraft Operations Facility (DAOF) in order to prepare for the 8AM takeoff of our first SARP flight.
After a 6:30AM preflight briefing by the P-3 pilots and crew, the first flight took off at 8AM with all of the Ustin group onboard.  The goal of this flight was to calibrate the MASTER instrument over Lake Tahoe (flying several lines at different altitudes over temperature targets) and to test all of the other instruments (AVOCET, WAS, and the UH instruments).  Onboard the P-3, the Ustin group got the opportunity to learn about and and assist in the operation of all of the instruments.  The flight was very smooth and the group returned with broad smiles after their 3-hour flight.


Flight track (in red) from the June 25th morning flight.

After lunch, the second flight (and first science flight) took off with half of the Blake group and half of the Kudela group onboard.  Thanks to our meteorologist, Dr. Fuelberg, we knew that the Santa Barbara Channel was going to be very clear and that we had the opportunity to collect fabulous, cloud-free data.


Altitude profile for the afternoon flight on June 25.  Note the low altitude over the LAX runway


Flight track (in red) for the June 25th afternoon flight. 


Those of us on the ground were able to chat with those onboard via a text-chatting application called x-chat.  Dr. Sherry Palacios, the ocean group mentor who was onboard the P-3, provided frequent updates about what was going on inside the plane.  After all of the science goals of the flight were completed (including a missed-approach over LAX, samples of clean marine air off of the coast and polluted air from the LA basin, and flight lines over the Santa Barbara Channel), the pilots gave all onboard a special treat by letting them experience zero gravity (for just a second).

At the end-of-day postflight briefing, everyone who flew for the first time received an Airborne Science Program pin from our pilot in a special ceremony.

Tuesday:
Fortune smiled on us yet again with clear weather over the Santa Barbara Channel!  After a group shot in front of the P-3, the first flight of the day took off for Santa Barbara.  After takeoff, the Ustin group left Palmdale to drive to Delano, CA for their field trip.


SARP 2012 group shot in front of the P-3 before takeoff on June 26, 2012


Flight track (in red) for the morning flight on June 26

The afternoon flight was extremely bumpy because most of it took place below the boundary layer.  The P-3 also flew 6 missed approaches over airports in the Los Angeles Basin on this flight!  Upon their return, many SARPians looked a little green but everyone was very excited about the amount of data that was collected.


Altitude profile for the afternoon flight on June 26.  Note the six low altitude passes over Los Angeles area airports


Flight track (in red) for the afternoon flight on June 26

Wednesday:
The Ustin group was in the field at a vineyard in Delano, CA taking ground-truth measurements while the P-3 flew overhead collecting remote sensing data with MASTER during both the morning and afternoon flights. 


Flight track (in red) for the morning flight on June 27


The P-3 as seen from a vineyard near Delano, CA (Image Credit: Kate Garner)


The Ustin group prepares for the P-3 overflight (Image Credit: Kate Garner)

In addition to the MASTER lines over the vineyards, we also collected air samples and air quality measurements over dairies, cow feedlots and oil fields in California’s Central Valley.


Flight track of the final SARP science flight (afternoon of June 27)


“Houston, we have cows.”  A cow feedlot in the California Central Valley as seen from the P-3


At the end of our final flight, our pilots treated us yet again to a brief zero gravity experience. 

The SARP faculty, mentors and students were all thrilled with how much data was collected during the six SARP flights!

Thursday:
One group (the Aquanauts) decided to forgo sleeping in so that they could watch an early ER-2 takeoff.  The ER-2 flies at such high altitudes (~70,000ft) that the pilot has to wear a spacesuit.  We watched as the pilot emerged from his life support vehicle, climbed aboard the ER-2 and took off.


SARP participants pose next to the ER-2


ER-2 pilot taps the nose of the plane for good luck
Later in the day, the P-3 departed the DAOF for its home in Virginia at the NASA Wallops Flight Facility.  We are so grateful to the P-3 pilots and crew for such fantastic flights and for making this experience possible!

Friday:
After packing up and checking out of the hotel in Palmdale, the Blake, Lefer, and Kudela groups departed for the Dryden Flight Research Center (DFRC).  Just outside the entrance to Edwards Air Force Base (DFRC is inside Edwards), we met up with the Ustin group who had left their field site in Delano, CA very early in the morning.  Once at DFRC, we were treated to a rare, behind the scenes tour that included the Global Hawk Unmanned Aerial Vehicles (UAV’s) and the Global Hawk control center.  We were also given an up close look at Dryden’s research fighter aircraft and many history-making aircraft such as the X-1E.

SARP 2012 poses by the X-1E


After lunch and a stop at the Dryden giftshop, all of SARP headed for the University of California Irvine, our new home for the next six weeks where students will analyze and interpret the data they collected onboard the P-3 Orion.