ESRL Global Monitoring Laboratory - Mauna Loa Observatory

Measurements at the Mauna Loa Observatory stopped after the 2022 eruption of the Mauna Loa volcano, when lava flow crossed the access road and took out power lines to the facility. The observatory remains inaccessible by vehicle and without power from the local utility company.

Observatory staff has established limited solar power in four observatory buildings and restored approximately 33 percent of the measurements onsite, including the Global Monitoring Laboratory and Scripps critical CO₂ records and other atmospheric measurements.

Media can contact: Theo Stein (303) 819-7409 (theo.stein@noaa.gov) or Karin Vergoth 303-632-6413‬ (karin.vergoth@noaa.gov)

Organization(s):

NOAA logo National Oceanic and Atmospheric Administration (NOAA),
Earth System Research Laboratory (ESRL)

What does this program measure?

The ESRL GMD Meteorology program measures ambient and dewpoint temperatures, relative humidity, precipitation (in inches), and wind speed and direction.

How does this program work?

The dewpoint hygrothermometer measures ambient and dewpoint temperatures, from which relative humidity is calculated. Precipitation is continuously measured (in inches) with a tipping bucket.

A Mauna Loa PC based system utilizes RS-485 serial communications to collect data from the instruments. The data is recorded as one minute averages, except for precipitation. Precipitation is measured as a daily total accummulation.

Measurement	Instruments	Frequency
Air Temperature	Aspirated thermistor, 2m, 9m, 37mm heights	continuous
Air Temperature	Max/Min thermometers, 2-m height	daily
Temperature gradient	Aspirated thermistor, 2m, 9m, 37m heights	continuous
Dew point temperature	Dew point hygrometer, 2m height	continuous
Relative Humidity	TSL 2m height	continuous
Pressure	Capacitance Transducer	continuous
Pressure	Mercurial barometer	5/week
Wind (speed and direction)	10m, and 38m heights	continuous

Why is this research important?

In order to monitor the trends in meteorological parameters, and to assist in the interpretation of other parameters such as aerosols.

Are there any trends in the data?

Day rose and night rose (below) show the wind direction at the observatory. Note that the night rose shows only the southerly component which is the desired downslope conditions.

MLO press and MLO temps (below) is the running record since 1977. There is a slightly increasing trend in the ambient temperature since 1977.