1. Observatory, Meteorology, and Data Management Operations
1.3. SAMOA OBSERVATORY
The environmental engineer position with the Samoa Observatory, American Samoa (SMO) was vacated in October 1995 after 2 years of service. The replacement electronic engineer was selected with arrival due in 1996.
Internet access for the SMO local area network (LAN) was made possible by the installation of a modem router; however, e-mail services will be the only feature taken advantage of due to the high cost of a phone call and the poor quality of the telephone lines in Samoa. Hopes were high when the phone company replaced the old cable that runs 915 m from the observatory to the main phone line; unfortunately, there was no noticeable improvement.
Due to ongoing deterioration of the remote Ekto sampling building, plans were made to replace it with a permanent, concrete wall structure. This new building will be just a little larger than the old one and located as close as possible to the existing walk-up tower. Construction began in November 1995 with an expected completion date of June 1996.
Termites continued to be a problem at house T-7. The garage was torn down and replaced with a carport because termites devoured most of the old structure. The house was also infested and had to be fumigated again; this slows down the feeding process but does not stop it.
Both of the aging observatory vehicles were replaced with new trucks. This resulted in much less time being spent by the staff dealing with the constant vehicle problems.
The standby generator allowed the observatory to continue operation through many blackouts. No major problems were encountered and the small ones were easily handled by the staff.
The observatory continues to be a favorite tourist attraction because of the beautiful views. The observatory is also a favorite with local science teachers who bring their classes on field trips. Visitors are always welcomed and given a tour if they wish to learn more about the observatory's function.
Table 1.5 summarizes the programs at SMO for 1994-1995. Further descriptions
of some of the programs follow.
TABLE 1.5. Summary of Measurement Programs at SMO in 1994-1995
|CO2||Siemens Ultramat-5E analyzer||Continuous|
|CO2, CH4||0.5-L glass flasks, through analyzer||1 pair wk-1|
|2.5-L glass flasks, MAKS pump unit||1 pair wk-1|
|CO2, CH4, CO, and 13C, 18O of CO2||2.5-L glass flasks, AirKit||1 pair wk-1|
|Surface O3||Dasibi ozone meter||Continuous|
|Total O3||Dobson spectrophotometer no. 42||4 day-1|
|N2O, CFC-11, CFC-12, CFC-113, CH3CCl3, CCl4||300-mL stainless steel flasks||1 sample wk-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 wk-1|
|CFC-11, CFC-12, CFC-113, N2O, CCl4, CH3CCl3||HP5890 automated GC||1 sample h-1|
|N2O||Shimadzu automated GC||1 sample h-1|
|Condensation nuclei||Pollak CNC||1 day-1|
|Global irradiance||Eppley pyranometers with Q and RG8 filters||Continuous|
|Direct irradiance||Eppley pyrheliometer with Q filter||Continuous|
|Eppley pyrheliometer with Q, OG1,||Discrete|
|RG2, and RG8 filters|
|Diffuse irradiance||Eppley pyrgeometer with shading disk and Q filter||Continuous|
|Air temperature||Thermistors (2)||Continuous|
|Dewpoint temperature||Polished mirror||Continuous|
|Mercurial barometer||1 wk-1|
|Wind (speed and direction)||Bendix Aerovane||Continuous|
|Precipitation||Rain gauge, tipping bucket||Continuous|
|Rain gauge, plastic bulk||1 day-1|
|CO2, 13C, N2O (SIO)||5-L evacuated glass flasks||1 set wk-1 (3 flasks set-1)|
|GAGE project: CFC-11, CFC-12,||HP5880 gas chromatograph||1 h-1|
|N2O, CH3CCl3, CCl4 (SIO)|
|Various trace gases (OGIST)||Stainless steel flasks||1 set wk-1 (3 flasks set-1)|
|Bulk deposition (DOE)||Plastic bucket||Continuous (1 bucket mo-1)|
|Ion exchange column||Continuous (1 filter mo-1)|
|Total suspended particulates (DOE)||High-volume sampler||Continuous (1 filter wk-1)|
|Total suspended particulates (SEASPAN)||High-volume sampler||Continuous (1 filter wk-1)|
|CH4,(13C/12C ratio) (Univ. of Wash.)||30-L pressurized cylinder||Biweekly|
|Light hydrocarbons (UCI)||1-L evacuated stainless steel flasks||3-4 flasks qtr-1|
|O2 (URI)||2.5-L glass flasks||2 pair mo-1|
|O2 (SIO)||3-L glass flasks||2 sets mo-1 (3 flasks set-1)|
SIO - Scripps Institution of Oceanography
OGIST - Oregon Graduate Institute of Science and Technology
UCI - University of California, Irvine
URI - University of Rhode Island
The Siemens analyzer has traditionally been one of the most trouble-free instruments at SMO. However, when it broke down and defied local attempts to fix it, the analyzer made a round trip to Boulder for repair and was back in service in less than a month.
The air-intake line on the mast broke in 1994 and again in 1995. The problem is probably wind-induced vibration in the tubing thus causing it to crack.
The AirKit flask air sampler was put into service for an intercomparison with the older Martin and Kitzis Sampler (MAKS) unit. Eventually the MAKS unit will be retired in favor of the AirKit's built-in condenser that removes moisture from the air.
The Dasibi began the period in good condition with the Control and Monitoring System (CAMS) still responsible for the digital data collection. CAMS had a few problems that were eventually dealt with but a fair amount of data will have to be entered by hand from the chart recording. A new PC-based data system was received, but several problems prevented it from being hooked up.
In May 1995 the Dasibi overheated and blew some circuits; onsite repair was not feasible, therefore, a replacement was obtained. Unfortunately, the replacement was also a used instrument with its own set of troubles. As of the end of 1995, the Dasibi was not working properly.
The Dobson worked well with only one small problem when the high voltage power supply had to be replaced.
The data acquisition program was updated and continues to work well.
The dome is aging fast in the corrosive sea-air and will have to be replaced soon.
Ozonesonde balloon launches were restarted in August 1995 after a break of several years. At the airport the National Weather Service made their balloon inflation facility available, including the use of hydrogen gas to fill the balloons. Releases were made weekly.
Nitrous Oxide and Halocompounds
The old Hewlett Packard (HP) data acquisition computer was replaced with a PC-based system. This was done in May 1995. Some problems were solved and some new ones were born. The good news was that system crashes were almost completely eliminated. The most perplexing problem was a lack of readable chromatograms. Good data was being produced and saved but for some reason the printouts were no good.
The new computer came with a network board and software installed, however, reliable communication has yet to be achieved. This could be due to the long, 200 m run of coaxial cable from the main building to the remote site where the computer is located.
As in the past, several site visits were made by CMDL personnel from Boulder. This regular, close attention is one good reason why this program is so successful.
In January 1995 data acquisition was switched from CAMS to the new solar radiation system. This was a big improvement.
The Pollak performed well for the most part; the only problems encountered were with the ammeter. Apparently these ammeters are becoming scarce and servicing old ones is a delicate operation.
The main blower that provides the steady flow of air from the top of the pipe to the instruments inside failed. The failure was not noticed for several months. A new blower was installed April 1994.
With the construction of a new sampling building in November 1995, occasional heavy activity near the air intake for the aerosol instruments had a noticeable effect on the data.
A new data acquisition system was installed January 1995. This was a major improvement with several benefits including 24-hour access via modem to real time data. Another benefit was the elimination of the chore of packaging and mailing the data to Boulder.
An Eppley pyrgeometer with a Q dome and a shading disk mounted to a tracker to measure diffuse irradiance was put online August 1995.
A major overhaul of the meteorological system occurred in July 1994. A new data acquisition system was installed and all of the old sensors were replaced with new ones. As with the new solar radiation system, data will be available in Boulder at any time via modem. Unfortunately, this convenient feature was hampered by the poor quality of the telephone communication system in Samoa.
The new system performed flawlessly for several months then gradually became afflicted by resets and hangups. This problem was never satisfactorily solved; the most likely suspect was excessive noise on the 485-communication line connecting all the sensors to the computer.
By the end of 1995, carbon dioxide (CO2) was the only program still using CAMS for data acquisition. The CO2 CAMS unit has done a fine job but some day it too will be retired in favor of a more modern system.
SIO GC. The Scripps Institution of Oceanography (SIO) gas chromatograph (GC) Nafion dryer used to dry the incoming air sample was upgraded. The new system is self-recharging thus eliminating the chore of replacing cartridges periodically.
SEASPAN. The SEAREX South Pacific Aerosol Network (SEASPAN) wind sensor cable was replaced with a new one; the old one had several splices that were suspected of degrading the signal. The wind speed transducer was also upgraded.
DOE. The Department of Energy (DOE) wet/dry rooftop collection
bucket was replaced with an ion exchange column in August 1995. At the same
time, the frequency at which samples were shipped out was increased to once
per week. This was done in response to the decision in France to resume nuclear
testing at Muroroa Atoll near Tahiti.