Summer 2000 Preliminary Flux Aircraft Data Research funded under grants DBI# 9604793, OPP #9732105 (ATLAS) Principle Investigator: Walter C. Oechel Professor of Biology and Director Global Change Research Group San Diego State University San Diego, CA 92182 (619) 594-6613 Web: http://sci.sdsu.edu/GCRG oechel@sunstroke.sdsu.edu For data questions contact: Joe Verfaillie Global Change Research Group San Diego State University San Diego, CA 92182 (619) 594-7421 josephv@sunstroke.sdsu.edu Rommel Zulueta Global Change Research Group San Diego State University San Diego, CA 92182 (619) 594-4462 zulueta@mail.sdsu.edu Flight line descriptions Based out of Barrow, Alaska, three transects have been flown. Flown most often is a North-South transect between Barrow and Atqasuk from 71° 30' 00.0" N by 156° 27' 00.0" W at the northern end to 70° 00' 00.0" N by 157° 45' 00.0" W at the southern end. This transect passes near three permanent year-round eddy towers operated by SDSU. Also flown, usually combined into a single flight is an East-West transect and a short transect over Lake Tusivoak. The East-West transect runs between 70° 50' 00.0" N by 155° 55' 00.0" W in the east and 70° 50' 00.0" N by 158° 05' 00.0" in the west. The Lake transect runs from 71° 08' 40.00" N by 156° 13' 00.0" W at its northern end to 71° 00' 30.00" N by 156° 03' 00.0" W at its southern end. Figure 3: Barrow area flight lines. The North-South transect covers a latitudinal gradient that has distinct changes in temperature, vegetation, precipitation, and soil moisture from the cooler, wetter coastal tundra in the north to the dryer, warmer inland tundra in the south. The Lake transect is designed to study the contribution of lakes and ponds, which make up a large portion of the coastal plain, to the carbon flux. The East-West transect attempts to minimize the gradients seen in the North-South transect, providing an alternate check of the system. Starting in the late spring of 2000, an intensive campaign was flown out of Barrow, Alaska from June 30 through September 9. This season produced more than 50 data flights in 33 days of flying. There were 41 days of inclement weather that prevented flights. The system and aircraft proved to be robust with only two days lost to instrumentation failure and aircraft maintenance. Aircraft Description: The San Diego State University (SDSU) Sky Arrow N272SA is a special variant of the original Sky Arrow 650TCN built by Iniziative Industriali Italiane (3I) in Italy. The SDSU Sky Arrow is a newly certified and is designated as the Environmental Research Aircraft (ERA). There are special modifications to the aircraft that make it highly suitable for ecological and atmospheric measurements as well as remote sensing. Modifications include: two bays in the belly of the aircraft for downward looking instruments and sensors a small instrument boom on the horizontal stabilizer mounting holes in the nose of the aircraft for a custom-built nose probe two upward ports in the fuselage that could be outfitted with upward looking sensors or a whole-airplane ballistic parachute. The ERA designation includes a special instrument array called the Mobile Flux Platform (MFP) designed in collaboration between San Diego State University, and the Air Resources Laboratory (ARL) Field Research Division (FRD) and the Atmospheric Turbulence and Diffusion Division (ATDD) of the National Oceanic and Atmospheric Administration (NOAA). Table 1: Specifications of the Sky Arrow Specifications Dimensions - Overall Height 2.56 m (8.40 ft) Length 7.60 m (24.94 ft) Length (with nose probe) 8.15 m (26.7 ft) Wing Span 9.68 m (31.76 ft) Seats 2 tandem Cabin length 2.68 m (7.67 ft) Cabin width 0.82 m (2.33 ft) Cabin height 1.43 m (4.08 ft) Empty Weight (Standard configuration) 426.4 kg (940.1 lbs.) Empty Weight (Flux instrument configuration) 459.9 kg (1013.9 lbs.) Maximum gross weight 650.0 kg (1,433 lbs.) Useful load 230.4 kg (508 lbs.) Payload with full fuel 181.4 kg (400 lbs.) Dimensions - Wings Wing Area 13.55 sq. m (145.9 sq. ft) Wing Loading (For 650 kg/1,433 lbs.) 48 kg/m (9.81 lbs./ft) Airfoil Modified Gottinga 398 Type and position of the wing Rectangular, Braced, High Number and type of spars 2, "C" type Aspect ratio 6.91 Dimensions - Ailerons Ailerons Frise type Area 0.76 sq. m (8.16 sq. ft) Dimensions - Flaps Wing flaps Flat type Area 0.76 sq. m (8.16 sq. ft) Dimensions - Horizontal Stabilizer Position and type of elevator High, "T" type Horizontal tailplane area 2.1 sq. m (22.60 sq. ft) Horizontal tailplane span 2.8 m (9.19 ft) Elevator area 0.8 sq. m (8.61 sq. ft) Trim area 0.18 sq. m (1.9 sq. ft) Dimensions - Vertical Stabilizer Vertical fin and rudder area 1.71 sq. m (18.41 sq. ft) Engine Powerplant Rotax 912F2 Cylinders 4 air cooled Cylinder heads Liquid cooled Displacement 1,211 liters (73.9 cu in) Power @ RPM 81 hp @ 5800 RPM (59.6 kW) Reduction gear ratio 2.2727:1 Deviation of the thrust axis 1.0º to the left (looking towards the propeller from the tail) only in the horizontal plane. Recommended TBO 1,200 hours Propeller Type Hoffmann, HO17FHM-167 148LD Description Two blade, fixed pitch, wooden composite Maximum propeller RPM 2,555 RPM (5,800 engine RPM) Diameter (66 in) Fuel Number and position of fuel tanks 1 tank in fuselage Fuel quantity 68 liters (18 gallons) Approved fuel grades AVGAS 100LL, MOGAS (90 octane min.) Performance Takeoff distance, ground roll 298.0 m (781 ft) Maximum demonstrated crosswind component 7.72 m/s (15 kt) Rate of climb (sea level) 18.9 mpm (600 fpm) Cruise speed @ 75% power 46.3 m/s (90 kts) Endurance @ 75% power 4.1 hours Fuel consumption 16.3 lpb (4.3 gph) Service ceiling 4114.8 m (13,500 ft) Landing distance, ground roll 135.0 (443 ft) Limiting and Recommended Airspeeds VX (best angle of climb) 57 kts (Indicated Airspeed) VY (best rate of climb) 65 kts (Indicated Airspeed) VA (maneuvering) 90 kts (Indicated Airspeed) VFE (max flap extended) 67 kts (Indicated Airspeed) VNO (max structural cruising) 104 kts (Indicated Airspeed) VNE (never exceed) 132 kts (Indicated Airspeed) VR (rotation) 45 kts (Indicated Airspeed) VS1 (stall, clean) 40 kts (Indicated Airspeed) VSO (stall, in landing configuration) 38 kts (Indicated Airspeed) Instrumentation: Instruments that are represented in this data set include: Quantities Measured Instrument/Equipment Manufacturer Fast response air temperature Micro-bead Thermistors (2) VECO Slow response air temperature Mean Reference Thermistor Newark/Thermometrics Differential corrected position and velocity NovAtel OEM GPS NovAtel Ground surface temperature Infrared temperature sensor Everest 4000 4GL Height above ground level Laser range finder Riegl LD90-3300HR Fast Response relative H2O and CO2 concentration Open-path IRGA & power supply NOAA/ATDD Net radiation Net radiometer Q*7 REBS Incoming and reflected PAR PAR quantum sensors (2) LiCor Data Description: The following data sets are raw data collected by the flux aircraft. An initial quality check has been performed however some data spikes and noise due to radio interference or weather conditions (rain, snow) remain. GPS positions have been correct through post processing differential correction using Waypoint Incorporated's GrafNav software. A flight's data set consists of multiple files starting with an MS Word document that describes the data found in one or more the associated text files. Each filename includes and eight digit flight ID and extension. Flight ID's are of the form: month, day, hour, minute (MMDDhhmm). Current extensions are: _fs,doc MS Word file containing data description for the flight _s#.txt South bound pass over the North-South transect with option number (#) if there are multiple passes in the same flight. _n#.txt North bound pass over the North-South transect with option number (#) if there are multiple passes in the same flight. _ts.txt South bound pass over Tusivoak Lake. _tn.txt North bound pass over Tusivoak Lake. _w.txt West bound pass over the East-West transect. _e.txt East Bound pass over the East-West transect. (JOSS 4/17/2002 Note that JOSS has converted the Word .doc files to ASCII .txt files) File List: PreliminaryAircraftData.doc - This file Data Files: 08011159_fs.doc 08011159_n.txt 08011159_s.txt 08011556_fs.doc 08011556_s.txt 08021854_fs.doc 08021854_n.txt 08021854_s.txt 08031941_fs.doc 08031941_n.txt 08031941_s.txt 08041628_fs.doc 08041628_n.txt 08041628_s.txt 08061714_fs.doc 08061714_n.txt 08061714_s.txt 08070114_fs.doc 08070114_n1.txt 08070114_n2.txt 08070114_s.txt 08082132_fs.doc 08082132_n.txt 08082132_s1.txt 08082132_s2.txt 08141420_fs.doc 08141420_n.txt 08141420_s.txt 08142056_e.txt 08142056_fs.doc 08142056_tn.txt 08142056_ts.txt 08142056_w.txt 08150908_fs.doc 08150908_n.txt 08150908_s.txt 08151542_fs.doc 08151542_n1.txt 08151542_n2.txt 08151542_s1.txt 08151542_s2.txt 08151542_s3.txt 08162128_fs.doc 08162128_s.txt 08261037_fs.doc 08261037_n.txt 08261037_s.txt 08261811_fs.doc 08261811_n.txt 08261811_s.txt 08271258_fs.doc 08271258_n.txt 08271258_s.txt 08301523_fs.doc 08301523_n.txt 08301523_s.txt 09010939_e.txt 09010939_fs.doc 09010939_tn.txt 09010939_ts.txt 09010939_w.txt 09011425_fs.doc 09011425_n.txt 09011425_s.txt 09011801_e.txt 09011801_fs.doc 09011801_tn.txt 09011801_ts.txt 09011801_w.txt 09020812_fs.doc 09020812_n.txt 09020812_s.txt 09021146_fs.doc 09021146_n.txt 09021146_s.txt 09031549_fs.doc 09031549_n.txt 09031549_s.txt 09040648_fs.doc 09040648_n.txt 09040648_s.txt 09061418_fs.doc 09061418_n.txt 09061418_s.txt 09081543_fs.doc 09081543_n.txt 09081543_s.txt 09091704_fs.doc 09091704_n1.txt 09091704_n2.txt 09091704_s1.txt 09091704_s2.txt