CalClim: California Climate Data Archive

CALIFORNIA CLIMATE WATCH
CURRENT ISSUE: August 2006

Read the full newsletter here: PDF format

Focus On: Climate Monitoring Networks

By Laura Edwards
Western Regional Climate Center

Learning what the climate is near your home, work or favorite vacation spot is easier now than ever, thanks to the array of weather and climate networks around the state.

As early as the mid-1800s weather has been regularly observed around the nation. In California, some weather stations have temperature, precipitation and snowfall records that date back to this period. The National Weather Service (NWS) manages the Cooperative Observer Network (COOP), which was created officially in 1890. This is now the oldest group of nationwide weather watchers, currently comprised of nearly 12,000 volunteers. The COOP Network currently has hundreds of active stations in California, with hundreds more that have taken observations at some point in the last 100 years.

Figure 1. The COOP station at Boca Reservoir, CA in 2005. From left to right this station includes: an evaporation pan, cotton region temperature shelter, and an 8 inch rain gauge.

The NWS provides equipment and training for the observers, who take manual observations every 24 hours, usually in the morning or evening. A smaller set of observers call in or use the internet to submit their data each day. When the COOP network was created, it was designed for agricultural purposes, but its usefulness has spread into many other areas. This primarily volunteer effort is essential to forecasters, emergency responders and others who rely on the latest weather information.

At month's end, each observer's record goes to the National Climatic Data Center, where it is archived and put in digital format, if it is not already. This may be thought of as the location where weather data turns into climate data. With the help of regional climate centers and state climatologists, the climate data archived at NCDC gets redistributed to researchers, students, historians, and many others.

As a result of the large numbers of participants and long duration of many records, the COOP has become been particularly useful for climate research, including climate variability and change. The basic variables that are measured once per day at these homes and businesses provide the core dataset for initializing weather and climate models, forming "ground truth" to forecast models, as well as learning about climate trends in individual cities.

Figure 2. San Francisco weather observations for January 1862, as published in Daily Alta California. From Climate Station Chronicles, edition 8, archived at NCDC.

Other weather observing networks for purposes other than climate monitoring have also become key pieces in the climate data puzzle. Airports have primarily taken hourly weather observations in support of flight operations, but with many airports having now been active for over half a century, their data has proven to be useful in a climatological sense as well.

The Remote Automated Weather Stations (RAWS) were designed for fire weather in forests, national parks and other remote areas. Some of these stations are now nearly 20 years old and can contribute to ongoing climate research in undisturbed areas. The World Meteorological Organization's definition of a "normal" period is 30 years, and RAWS is approaching that threshold. RAWS stations record hourly data, previously seen almost exclusively at airports, and have been able to tell us much about daily fluctuations in temperature, wind, precipitation, and even fuel moisture and solar radiation at many locations.

California is home to a few other unique weather observing networks of their own. Department of Water Resources operates the California Snow Survey and California Irrigation Management Information System (CIMIS). The California Snow Survey's snow course data dates back nearly 100 years. Modern equipment has been added to the once a month manual snow measurements, so that snowfall and precipitation data can be updated hourly, or even more frequently, at many locations in the Sierra Nevada. California Snow Survey complements the nationwide SNOTEL (Snowpack Telemetry) network. CIMIS is primarily intended for irrigation management, but this too has proved to be useful for those interested in the climate of agricultural areas.

Next time you need to know the climate or weather in your backyard or outside your office window, call the NWS or your regional or state climate office. The amount of information and variety of sources can tell a more complete climate story than ever.

For More Information:
1. NWS Cooperative Observer Program website: http://www.nws.noaa.gov/om/coop/what-is-coop.html 2. California Irrigation Management Information System: http://wwwcimis.water.ca.gov/cimis/welcome.jsp

Last updated 9/21/06.

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California Climate Watch Archive All data in the Climate Watch is provisional and subject to change. Please contact us for updated and quality-checked data. *Previous California Climate Watch* Issues 2006 2005 2004 Monthly Weather Summaries** 2006 2005 2004	CALIFORNIA CLIMATE WATCH CURRENT ISSUE: August 2006 Read the full newsletter here: PDF format Focus On: Climate Monitoring Networks By Laura Edwards Western Regional Climate Center Learning what the climate is near your home, work or favorite vacation spot is easier now than ever, thanks to the array of weather and climate networks around the state. As early as the mid-1800s weather has been regularly observed around the nation. In California, some weather stations have temperature, precipitation and snowfall records that date back to this period. The National Weather Service (NWS) manages the Cooperative Observer Network (COOP), which was created officially in 1890. This is now the oldest group of nationwide weather watchers, currently comprised of nearly 12,000 volunteers. The COOP Network currently has hundreds of active stations in California, with hundreds more that have taken observations at some point in the last 100 years. Figure 1. The COOP station at Boca Reservoir, CA in 2005. From left to right this station includes: an evaporation pan, cotton region temperature shelter, and an 8 inch rain gauge. The NWS provides equipment and training for the observers, who take manual observations every 24 hours, usually in the morning or evening. A smaller set of observers call in or use the internet to submit their data each day. When the COOP network was created, it was designed for agricultural purposes, but its usefulness has spread into many other areas. This primarily volunteer effort is essential to forecasters, emergency responders and others who rely on the latest weather information. At month's end, each observer's record goes to the National Climatic Data Center, where it is archived and put in digital format, if it is not already. This may be thought of as the location where weather data turns into climate data. With the help of regional climate centers and state climatologists, the climate data archived at NCDC gets redistributed to researchers, students, historians, and many others. As a result of the large numbers of participants and long duration of many records, the COOP has become been particularly useful for climate research, including climate variability and change. The basic variables that are measured once per day at these homes and businesses provide the core dataset for initializing weather and climate models, forming "ground truth" to forecast models, as well as learning about climate trends in individual cities. Figure 2. San Francisco weather observations for January 1862, as published in Daily Alta California. From Climate Station Chronicles, edition 8, archived at NCDC. Other weather observing networks for purposes other than climate monitoring have also become key pieces in the climate data puzzle. Airports have primarily taken hourly weather observations in support of flight operations, but with many airports having now been active for over half a century, their data has proven to be useful in a climatological sense as well. The Remote Automated Weather Stations (RAWS) were designed for fire weather in forests, national parks and other remote areas. Some of these stations are now nearly 20 years old and can contribute to ongoing climate research in undisturbed areas. The World Meteorological Organization's definition of a "normal" period is 30 years, and RAWS is approaching that threshold. RAWS stations record hourly data, previously seen almost exclusively at airports, and have been able to tell us much about daily fluctuations in temperature, wind, precipitation, and even fuel moisture and solar radiation at many locations. California is home to a few other unique weather observing networks of their own. Department of Water Resources operates the California Snow Survey and California Irrigation Management Information System (CIMIS). The California Snow Survey's snow course data dates back nearly 100 years. Modern equipment has been added to the once a month manual snow measurements, so that snowfall and precipitation data can be updated hourly, or even more frequently, at many locations in the Sierra Nevada. California Snow Survey complements the nationwide SNOTEL (Snowpack Telemetry) network. CIMIS is primarily intended for irrigation management, but this too has proved to be useful for those interested in the climate of agricultural areas. Next time you need to know the climate or weather in your backyard or outside your office window, call the NWS or your regional or state climate office. The amount of information and variety of sources can tell a more complete climate story than ever. For More Information: 1. NWS Cooperative Observer Program website: http://www.nws.noaa.gov/om/coop/what-is-coop.html 2. California Irrigation Management Information System: http://wwwcimis.water.ca.gov/cimis/welcome.jsp Last updated 9/21/06.