Flux Towers Transect

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The Southern Sierra CZO operates eddy co-variance flux towers installed at four different locations varying from 405-2700 meters.

Transect area: 568 km2   Area

405 - 2700 m   Elev

© Southern Sierra Critical Zone Observatory


igneous-felsic intrusive

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Setting & Research
Overview Maps
Dynamic Map
  • Setting & Research

    The Southern Sierra Critical Zone Observatory installed its first flux tower near the top of the P301 subcatchment located inside the Providence Creek headwaters.  Three additional flux towers have been installed, creating a west-to-east transect ranging from low-elevation oak savannah to high-elevation subalpine forest.

    San Joaquin Experimental Range (SJER) - Oak/Pine savannah

    • Installed October 2009
    • Elevation 405 m
    • Tavg 14.4°C, Twinter 9.4°C
    • Annual precipitation ~500 mm
    • 0 days with snow
    • Tree height 11 m
    • 25% tree cover

    Soaproot Saddle - Ponderosa Pine forest

    • Installed September 2010
    • Elevation 1160 m
    • Tavg 10.9°C, Twinter 5.4°C
    • Annual precipitation 870 mm
    • 11 days with snow
    • Tree height 29 m
    • 63% tree cover

    P301 - Midmontane forest

    • Installed September 2008
    • Elevation 2015 m
    • Tavg 8.9°C, Twinter 3.7°C
    • Annual precipitation <1000 mm
    • 130 days with snow
    • Tree height >30 m
    • 53% tree cover

    Short Hair Creek - Subalpine forest

    • Installed October 2009
    • Elevation 2700 m
    • Tavg 4.1°C, Twinter -0.5°C
    • Annual precipitation <1100 mm
    • 184 days with snow
    • Tree height 22.4 m
    • 31% tree cover

    San Joaquin Experimental Range flux tower © Southern Sierra Critical Zone Observatory

    Soaproot Saddle flux tower, cranked down for maintenance. © Southern Sierra Critical Zone Observatory

    Providence P301 flux tower © Southern Sierra Critical Zone Observatory

    Short Hair Creek flux tower © Southern Sierra Critical Zone Observatory

  • Overview Maps

    Southern Sierra CZO overview map

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    Southern Sierra CZO flux tower transect map

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  • Dynamic Map

    To fully zoom into a small area, you may need to visit the "Map" button and uncheck "Terrain" view.

  • Data

    National - Climate, Flux Tower, Streamflow / Discharge - CUAHSI WDC web services (1968-2015)
    7 components    Boulder Creek Watershed, Christina River Basin, Jemez River Basin, Santa Catalina Mountains, El Verde Field Station, Northeastern Puerto Rico and the Luquillo Mountains, Rio Blanco, Rio Mameyes, Susquehanna Shale Hills Critical Zone Observatory, Providence Creek Headwater Catchments (1660 - 2117 m elevation), Flux Towers Transect, Wolverton Basin (2230 - 2700 m elevation), Other instrumented sites    Climatology / Meteorology, Hydrology, Soil Science / Pedology    Boulder Creek Critical Zone Observatory, Catalina-Jemez Critical Zone Observatory, Luquillo Critical Zone Observatory, Shale Hills Critical Zone Observatory, Southern Sierra Critical Zone Observatory, Christina River Basin Critical Zone Observatory

    Southern Sierra Nevada - LiDAR, Digital Elevation Model (DEM), Snow Survey - Snow-on, Snow-off Flyover (2010)
    2 components    Providence Creek Headwater Catchments (1660 - 2117 m elevation), Flux Towers Transect, Wolverton Basin (2230 - 2700 m elevation), Other instrumented sites    GIS / Remote Sensing, Hydrology    Qinghua Guo, Roger Bales, National Center for Airborne Laser Mapping

  • Photos

    SSCZO - Flux Towers

    An eddy covariance flux tower is located near the top of the P301 watershed. Instruments collect data on temperature, relative humidity, and fluxes of carbon dioxide and water vapor to determine the physiological responses of the site (for example, how photosynthesis increases with light) and summed over a year to determine the carbon balance of a site (how much carbon it is gaining or losing). Three other flux towers have been instrumented at different elevations with the Sierras including the San Joaquin River, Soaproot, and Short Hair Creek.

    This west-east transect spans elevation gradient from 400 m to 2700 m. The change in elevation is accompanied by a slight increase in precipitation, but the main change is a shift from rain-dominated precipitation to snow-dominated precipitation. The climatic shift plays out in other ways as well. At lower elevations, high temperatures and low water availability limit evapotranspiration by vegetation. Meanwhile, forest activity (evapotranspiration) at higher elevations is limited by cold winter temperatures. There is a sweet spot at middle elevations of yera-round evapotranspiration and forest activity.

    Photo galleries of each flux tower are available: San Joaquin Experimental Range;  Soaproot SaddleProvidence subcatchment P301; and Short Hair Creek.

    SSCZO - Instruments

    Hundreds of instruments and sensors have been deployed in the primary SSCZO research site of the Providence Creek watershed as well as in Wolverton basin.  Additional SSCZO flux towers and instruments have also been installed at the San Joaquin Experimental Range, Soaproot Saddle, and Short Hair Creek.

    Explore more photos of the intstuments and sensors used by SSCZO.

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  • Geology

    • igneous-felsic intrusive

    All of the flux towers lie within the Sierra Nevada Batholith, a collection of geochemically and texturally heterogeneous igneous plutons (intrusions) that were emplaced in the Mesozoic. The bedrock geology is well mapped at each of the sites; each site lies on a separate 15’ quadrangle mapped by the USGS in the 1960s-1980s. Primary unit descriptions below are taken from the individual maps, with additional details and naming modifications taken from a more recent USGS Professional Paper (Bateman 1992). Brief information is provided below, with more complete descriptions provided on each page.
    The two lower elevation sites, SJER and Soaproot Saddle, lie exclusively within one rock type. The two higher elevation sites, P301 and Short Hair Creek, have multiple rock types exposed near the towers. The highest elevation site, Short Hair Creek, was glaciated in the Pleistocene.

    SJER – 406 m elevation
    Quad: Millerton Lake
    Ward Mountain Trondhjemite (Kw) (formerly Leucotonalite of Ward Mountain)

    Soaproot Saddle, 1163 m elevation
    Quad: Shaver Lake
    Bass Lake Tonalite (Kbl, formerly Tonalite of Blue Canyon)

    P301, 2018 m elevation
    Quad: Huntington Lake
    Dinkey Creek Granodiorite (Kdc, formerly Granodiorite of Dinkey Creek)

    Short Hair Creek, 2703 m elevation
    Quad: Blackcap Mountain
    This site was glaciated in the Pleistocene (Gillespie and Zehfuss 2004) and is situated on glacial till. The bedrock immediately below the tower is of unknown composition. However, two different bedrock units are exposed within 500 m of the tower (Bateman 1965).
    Aplite and felsic quartz monzonite dikes (Kap)
    Granodiorite of Dinkey Creek (Kdc, see description for P301)

    (With thanks to W. Hahm for compiling information)