Hawaii Ocean Time-series (HOT)
in the School of Ocean and Earth Science and Technology at the University of Hawai'i

SHIPBOARD METEOROLOGICAL OBSERVATIONS AND NDBC BUOY

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SUMMARY: Basic meteorological and sea surface observations are recorded by ship's crew and HOT program personnel. These data are used in support of the CTD measurements and discrete water sample analyses. In addition, continuous environmental data are recorded at a NOAA-NDBC buoy located to the northwest of Station ALOHA.


1. Introduction

The surface ocean is inexorably tied to atmospheric forcing, including such processes as surface winds, solar radiation and heat flux. These processes, in turn, affect mixed layer depth and the distributions of nutrients and microorganisms. The stochastic variability of the north Pacific Ocean gyre demands a continuous observation program to fully assess upper water column variability. These important environmental data can only be collected with remote meteorological buoys, equipped with appropriate sensors.

2. Shipboard Meteorological Observations

Each month while the research vessel is supporting the water sampling and measurement program at Station ALOHA, basic meteorological observations (including sea surface temperature, relative humidity, cloud cover, etc.) are made on 4-hour intervals by the WOCE program personnel. In addition to these measurements, the bridge weather logs, sail-loop data and other meteorological observations made the ship's officers and crew are also incorporated into the HOT program data base. Finally, continuous measurements of photosynthetically available radiance (PAR) are made by the GOFS program personnel for the duration of each cruise.

3. NDBC Buoy Measurements

We have recently obtained a nearly continuous 9 year record of meteorological and upper water column data from the National Oceanographic Data Center in Washington, D.C. for environmental conditions near Station ALOHA. Since Feb 1981, data have been collected from NDBC buoy #51001 located to the northwest of Station ALOHA (23° 23'59"N, 162° 8'00"W). Data include: air temperature (in °C, to nearest 0.1), barometric pressure reduced to sea-level (in mB, to nearest 0.1), wind speed as 8.5 minutes average (in m sec-1, to nearest 0.01), wind direction as 8.5 minutes average (in degrees from true N to nearest 0.1), significant wave height corrected for low frequency noise (in m, to nearest 0.1), average wave period (in sec, to nearest 0.1), sea surface temperature (in °C, to nearest 0.01), wind gust (in m sec-1 to nearest 0.01) and wave spectrum data.

The file structure is the standard NODC 9x120 character records logged on hourly intervals. The data, recorded on magnetic tape, are obtained from NODC, approximately three months after collection. At the University of Hawaii, the data are translated into ASCII file format whereupon they are further analyzed by HOT program personnel. It is also possible to receive these data in real time from the NOAA weather service as this information is also used for local weather and surf forecasting.