1.2.1. OPERATIONS

Data collection continued at the Barrow Observatory, Barrow Alaska (BRW) without any major interruptions during 1994-1995. Data collection system upgrades improved the quality of data for several programs and allowed remote access to data by personnel in Boulder. A second 486 computer was added to the station inventory allowing access to the Internet and, by using PC/TCP software, allowing access to email. The Control and Monitoring System (CAMS) units reached the end of their useful life and replacement data acquisition systems were installed.

The future of the distant early warning (DEW) Line site remains in question with the only certainty being a reduction in personnel. At this time it is uncertain how changes may affect operations at BRW. Assurances were given by the Air Force that any changes made at the DEW Line will have the smallest possible impact on the observatory while meeting the changing needs of the Air Force.

For the second time in the 23-year history of BRW, the exterior of the main building was painted during the summer of 1994. Plans are still in the works for other much needed upgrades to the building. A new pump enclosure was built at the end 1995 to help the sound abatement program at the observatory. Sound levels were measured at 85 dB at one time and have been reduced to 66 dB. A further reduction is expected when the enclosure is finished and all pumps are installed. On two separate occasions snow and/or ice blocked the sampling stack and had to be cleaned. Cleaning was done by removing the cap at the bottom of the stack and tapping the stack near the top with a long pole. This dislodged the blockage and allowed the normal volume of air to pass through the stack.

A change in personnel occurred in April 1994 when the technician left for a position in Boulder. A replacement arrived shortly before his departure and assumed the technician duties in a very smooth transition. The station chief celebrated his tenth year at BRW during 1994 and in 1995 was asked to serve on the Barrow Restoration Advisory Board. This Board is concerned with the cleanup of toxic waste spills by the Navy and the Air Force at the old National Arctic Research Laboratory site and the DEW Line site.

Vehicles ran well with the sole exception of a cracked piston in one of the snow machines. It was repaired and the snow machine was returned to service without interruption to the daily routine. The Naval Surface Warfare Center donated a snow machine to the station in the summer of 1995.

The NOAA housing was connected to the city water supply during the summer of 1995. Water no longer must be hauled in by truck; the storage tank at the CMDL unit will be removed.

During 1994-1995 BRW was visited by 158 registered guests. Among these were Congressional staff members, the NOAA Administrator, and researchers from China, Japan, and Russia. There were several visits by personnel from the National Science Foundation (NSF), the Arctic Research Consortium of the U.S. (ARCUS), and the U.S. Air Force and Navy.

1.2.2. PROGRAMS

Aerosols

The Thermo Systems Incorporated (TSI) condensation nucleus counter (CNC) uses butyl alcohol to saturate particles and passes them through a laser diode to count CN. The instrument continued to run well throughout the year. Problems were found, however, in noise levels in the signal. There appears to be a possible ground loop problem causing noise on the Campbell Scientific, Inc. (CSI) data recorder. On two separate occasions the optics and air path were cleaned of debris buildup and the alcohol was drained due to moisture absorption.

The nephelometer measures backscatter at four wavelengths. It ran well this period except for the ball valve in the blower system. A shaft made of inferior plastic broke and the change between filtered air and ambient air could not take place. Station personnel machined a new part at the local high school and the unit was returned to operation the next day. Problems with the noise mentioned above was also found in the nephelometer signal.

Solar Radiation

The CSI data acquisition system (DAS) operated well all year with the only problem being a shorted input channel. Signal lines were moved to another terminal and the data flow continued with only a minor interruption.

Blowers were installed on the pyranometers and pyrgeometers during 1994. They ran well during the 1994-1995 season and helped keep the snow and ice from building up on the domes. The air flow across the domes and the dry BRW air combined to sublimate any ice buildup that did occur.

Instruments are taken off line each year in November and installed again in February of the following year. During this downtime any calibrations that are needed are performed in Boulder and repairs made as needed. During the 1995 winter season, all instruments were returned to Boulder with the exception of the up-facing and down-facing pyrgeometer infrared instruments which were left online. The filter wheel normal incidence pyrheliometer (NIP), normally kept in the Dobson dome, was also returned to Boulder.

Carbon Cycle

Carbon Dioxide Nondispersive Infrared Analyzer. The Siemens Ultramat 5-E continues to be the station instrument and ran well the entire period. Data trends continue to show the normal seasonal variations in BRW data. Highs of up to 370 ppm and lows to 340 ppm were noted.

A static discharge damaged the electronics in the Linseis chart recorder. The recorder was taken out of service for approximately 3 weeks while replacement parts were ordered.

Future plans call for replacing the CAMS DAS with a Hewlett Packard (HP) UNIX-based workstation. The strip chart recorder will be taken out of service as well. These changes are being planned for sometime during the spring of 1996.

Methane. A Carle GC uses flame ionization to measure CH₄. Data is recorded by an HP integrator and stored on floppy disks. Noise in the data for a short time was the only problem encountered.

Data trends continue as in past years with data ranging between highs of over 1950 ppbv and lows of 1750 ppbv. Growth exhibited a slightly negative trend in 1994.

Carbon Monoxide. A Trace Analytical gas chromatograph (GC) has been in continuous operation since 1991. CO mixing ratios range between approximately 150 ppbv and 250 ppbv. Flask data are available since 1990.

The system ran well during the entire period with no significant downtime. Data are measured by an HP A/D, processed on an HP integrator, recorded on an HP floppy disk drive, and sent to Boulder for final analysis.

Flask Samples. Flask samples were collected as scheduled based on availability of flasks. The carbon dioxide (CO₂), methane (CH₄), carbon monoxide (CO) and isotopic data from the flask samples can be found in sections 2 and 5 of the report. No major problems were encountered.

Meteorology

A new data collection system was installed during April 1994. The new system replaces the aging CAMS DAS and is a ruggedized 486 computer rack mounted for ease of use. Metrabyte modules are used as an interface between the sensors and DAS. The new system was connected to the BRW local area network (LAN) and data are available to the CMDL Meteorological group on demand. Data are transferred to Boulder once per day and a quick look for quality control assures a higher level of confidence in the data.

Calibrations are performed twice each year, once in the spring and once in the fall, to assure correct operation of all sensors. Temperature probes are checked and corrected, if needed, to 0.2°C. Alignment of the wind sensor is checked and the speed accuracy is traceable to NIST standards.

CAMS

As mentioned previously, the MET CAMS was replaced during April 1994. The aerosol solar radiation (ASR) CAMS was replaced during 1993. The only programs still running on CAMS are the CO₂ and the Dasibi. Plans call for replacing the CO₂ early in 1996. The CAMS system has had minimal problems during its entire 10-year lifetime, but parts have become too hard to find and a replacement needed to be found.

Ozone

Surface Ozone. Surface ozone, as measured by the Dasibi, continues to be one of the long-term staples of the BRW measurement regime. The Dasibi was temporarily affected by the blockage of the stack with snow. A new display and logic board was installed when the old board malfunctioned. Otherwise the system ran without major problems.

Dobson. BRW continues to operate Dobson no. 91. Long-term trends in the data continue as in past years with seasonal highs in the spring and lows occurring in the fall. Values in April can be as high as 440 Dobson Units (DU) and lows in September can be as low as 290 DU. The Dobson is not run during the winter months due to lack of sunlight, but the calibration regime is continued to assure proper functioning when the sun rises the next year. Observations are usually made from February until October.

Nitrous Oxide and Halocarbons

Gas Chromatographs. The HP DAS was replaced with a 486-based system during the summer of 1995. The new system was connected to the LAN and allows access to the data by Boulder personnel. The new system is considerably more reliable than the HP computer used in the past. New data handling schemes are possible that were not with the HP-based system. The GC's remain unchanged. Currently there is an HP-5890 and a Shimadzu GC-8A onsite running every half hour, alternating between calibration gas and ambient air.

Flask Samples. Flask samples were collected as scheduled and available. Data show a very distinct leveling of the chlorofluorocarbon-11 and -12 (CFC) mixing ratio. This is attributed to the Montreal Protocol, which phases out production of certain CFCs. A detailed list of the chemicals analyzed by the CMDL Nitrous Oxide and Halocompounds Group (NOAH) can be found in Table 1.4.

Cooperative Projects

A comprehensive list of all BRW cooperative projects and affiliation is given in Table 1.4. Only projects with special problems or unusual occurrences are mentioned here.

TABLE 1.4. Summary of Measurement Programs at BRW in 1994-1995

Program			Instrument	Sampling Frequency
Gases
	CO2		Siemens Ultramat 5E analyzer	Continuous
			3-L glass flasks	1 pair wk-1
			0.5-L glass flasks, through analyzer	1 pair wk-1
	CO2, CH4, CO, and 13C/12C and 18O/16O of CO2		0.5-L glass flasks, P3 pump unit	1 pair wk-1
	CH4		Carle automated GC	1 sample (12 min)-1
	Surface O3		Dasibi ozone meter	Continuous
	Total O3		Dobson spectrophotometer no. 91	3 day-1
	CO2		Siemens Ultramat 5E analyzer	Continuous
	N2O, CFC-11, CFC-12, CFC-113, CH3CCl3, CCl4		300-mL stainless steel flasks	1 sample mo-1
	N2O, CFC-11, CFC-12, CFC-113, CH3CCl3, CCl4, SF6, HCFC-22, HCFC-141b, HCFC-142b, CH3Br, CH3Cl, CH2Cl2, CHCl3, C2HCl3, C2Cl4, H-1301, H-1211, H-2402, HFC-134a		850-mL stainless steel flasks	1 sample mo-1
	CFC-11, CFC-12, CFC-113, N2O		HP5890 automated GC	1 sample h-1
	CCl4, CH3CCl3
	N2O		Shimadzu automated GC	1 sample h-1
	CO		Trace Analytical GC	1 sample (6 min)-1
Aerosols
	Condensation nuclei		Pollak CNC	1 day-1
			T.S.I. CNC	Continuous
	Optical properties		Four-wavelength nephelometer	Continuous
	Black carbon		Aethalometer	Continuous
Solar Radiation
	Global irradiance		Eppley pyranometers with Q and RG8 filters	Continuous
	Direct irradiance		Tracking NIP	Continuous
			Eppley pyrheliometer with Q, OG1	Discrete
			RG2, and RG8 filters
	Albedo		Eppley pyranometer	Continuous
Terrestrial (IR) Radiation
	Upwelling and downwelling		Eppley pyrgeometers	Continuous
Meteorology
	Air temperature		Thermistor, 2 levels	Continuous
			Max.-min. thermometers	1 day-1
	Dewpoint temperature		Dewpoint hygrometer	Continuous
	Pressure		Capacitance transducer	Continuous
			Mercurial barometer	Discrete
	Wind (speed and direction)		R.M. Young aerovane	Continuous
	Precipitation		Rain gauge, tipping bucket
Cooperative Programs
	Total surface particulates (DOE)		High-volume sampler (1 filter wk-1)	Continuous
	Precipitation gauge (USDA)		Nipher shield, Alter shield, 2 buckets	1 mo-1
	Magnetic fields (USGS)		3-Component fluxgate magnetometer and total field proton magnetometer	Continuous
			Declination/inclination magnetometer sample	6 sets mo-1
	Various trace gases (OGIST)		Stainless steel flasks	1 set wk-1(3 flasks set-1)
	CO2, 13C, N2O (SIO)		5-L evacuated glass flasks	1 pair wk-1
	CH4 (Univ. of Calif., Irvine)		Various stainless steel flasks	1 set (3 mo)-1
	Earthquake detection		Seismograph	Continuous, check
	(Univ. of Alaska)			site 1 wk-1
	13CH4 (13C/12C) (Univ. of Washington)		35-L stainless steel flasks	1 (2 wk)-1
	14CO (Univ. of Washington)		A150 aluminum cylinders filled to 2000 psi	1 (3 wk)-1
	UV monitor (NSF)		UV spectrometer	1 scan per 0.5 hour
	Magnetic fields (NAVSWC)		3He sensors	Continuous
	Sound Source (DOE)		RASS	1 hr-1
	Ice Buoys (NOS)		Ice buoys	Continuous
	O2 in air (Univ. of Rhode Island)		3-L glass flasks	1 pair (2 wk)-1
	Magnetic micropulsations (Univ. of Tokyo)		Magnetometer and cassette recorder	Continuous
	Aerosol chemistry (Univ. of Alaska)		High-volume sampler	3 wk-1

DOE/ARM. The Department of Energy (DOE) Atmospheric Radiation Measurement (ARM) Laboratory is planning a long-term program of atmospheric radiation monitoring to collect data for use in climate models. The largest single unknown is the effect of cloud cover on the climate. BRW has been chosen as one of three sites worldwide to monitor these variables. Since late 1993, in cooperation with the North Slope Borough, Department of Wildlife Management, DOE has been testing an active Radio Acoustic Sounding System (RASS). Its impact on wildlife near the site is monitored.

NOAA/Navy Joint Ice Center. In CMDL Summary Report No. 22 a brief discussion of this project was given. Since that time new buoys and a new DAS have been added to the project. Phone access to the data is now possible. This project has yielded much useful data as to the type of buoy and the problems encountered with arctic deployment.

University of Tokyo. A new data recorder was installed in 1995 and this project was reactivated. The recorder, with high gain amplifiers, is connected to a set of three search coil sensors that point to magnetic north, magnetic east, and vertical. Magnetic micropulsations of 0.001-5 Hz are recorded and the tapes are sent to the University of Tokyo for analysis of magnetic storm effects. Each week during the tape change, a time check to the nearest second is performed and the system is checked during the week for proper functioning.

University of Alaska, Fairbanks. A trace metals project was reactivated this time period. This is the reactivation of the former University of Rhode Island (URI) filter project discontinued in 1988. A filter is connected to a hi-vol pump and samples are collected three times per week. Filters are sent to the University of Alaska where they are stored for future analysis for trace metals associated with arctic haze. At the present time no analysis is being performed.

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