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Taking the Temperature of Norris Geyser Basin

In 2003, activity in the Norris Geyser Basin increased and scientists logged higher ground temperatures and witnessed a greater number of geyser eruptions. In order to better understand the hydrothermal system at Yellowstone, a temporary network of monitoring equipment was installed, which was eventually followed by the installation of a more robust network.

An article titled Tracking Yellowstone's Activity is published in the April 2011 issue of Earth Magazine. It focuses on the scientific research underway at Norris Geyser Basin.

The Norris Geyser Basin has long been known as highly dynamic, and recent evidence implies that the area may be highly responsive to earthquakes and ground movements associated with inflation and deflation of the Yellowstone Caldera. In an effort to better document changes in water flow and heat discharge from different parts of the basin, YVO recently installed a series of radio-equipped temperature sensors. The equipment was purchased and installed with funds made available through the American Reinvestment and Recovery Act (ARRA).

How it Works

Ten temperature sensors are located in various stream channels and thermal features within the Norris Geyser Basin. The units are battery-powered and are sufficiently small that they can be placed around the geyser basin in an unobtrusive manner. Currently, they are programmed to record temperatures every 2 minutes. The radios transmit the recorded values daily to YVO (daily transmissions preserve batteries compared with more frequent data transfer). Automatic plots are then generated to provide daily, weekly and monthly plots of temperature values. Additional information on the temperature sensors and radios is available from the manufacturer, Marathon Products, Inc.* The new system has several advantages to both YVO and the public. First, data can be viewed within 24 hours of measurement, allowing rapid assessment of changing conditions. Equipment malfunctions can be rapidly detected, enabling us to identify and correct any problems. Lastly, if needed, the equipment can be queried in real-time by YVO scientists.

About the Measurement Sites

Ten sites are currently monitored. Three sensors are in geyser outlet channels, two are in hot pools, three are in stream channels, one measures soil temperature and a control site measures the air temperature at a nearby cold lake. The data can also be compared with data from the nearby Tantalus Stream Gage, which measures water flow and temperature of Tantalus Creek (the dominant drainage from Norris Geyser Basin). Unlike the radio-equipped temperature sensors, the stream gage utilizes a sizeable solar panel and sends data every 15 minutes via a satellite uplink.

GEYSER OUTLET CHANNELS (Click site names below to access temperature graphs)

Rapid temperature increases in geyser outlet channels typically reflect increases in flow due to eruptions of the nearby thermal feature. In the graph below, as an example, temperature measurements taken from Constant Geyser on September 20, 2010 indicate an eruption approximately every 40 minutes.

POOLS (Click site names to access temperature graphs)

Water temperature is measured beneath the pool surface. Temperature increases may reflect increased inflow of thermal water. Sudden decreases in temperature could be a result of a drop in water level beneath that of the temperature probe. This will usually result in large diurnal (24-hour) variations as the probe measures air temperature instead of water temperatures. Smaller diurnal variations are normal in pools.

The sudden drops in temperature in the plot below from Tantalus Above Reservoir are due to rain events on August 30, 2010 that added significant volumes of cold water to the small streams within Norris Geyser Basin. The temperature drops at 09:00, 13:30, 18:00 and 20:50 were present in all the temperature sensors placed in stream channels and most of those within hot pools.

STREAM CHANNEL TEMPERATURES (Click site names to access temperature graphs)

These temperatures reflect both meteorological conditions (solar radiation and air temperature) and the amount of flow from nearby thermal features. Rapid temperature increases can reflect geyser eruptions or other changes in water discharge. Rapid temperature drops may be caused by precipitation. Comparison of the different channel temperatures (as well as the air-temperature control station) can reveal specific parts of the basin affected by increased hydrothermal discharge.

The example plot below reflects diurnal (daily) variations in the stream water temperature at Porcelain Tributary from September 2 to 5, 2010. The daily warming cycle is due to solar radiation and (to a lesser extent) the related increase in air temperature.

OTHER (Click site names to access temperature graphs)

The plot below for Nuphar Air during the week of September 14, 2010 shows a dramatic downward spike which occurred during batter replacement. This is not a signal of temperature change. The notable humped patterns on 9/11 through 9/13 are diurnal (daily) temperature variations, which are are especially common on sunny days where the air temperature increases greatly during daylight hours.