Matt Meadows (Field Manager, UC Merced) checks on an instrument on the P301 flux tower.

Anemometer measuring wind speed and direction.

Ultrasonic anemometer on the P301 flux tower measures wind speed and direction in 3 dimensions. Data is connected to gas samples taken every quarter second at the filters on the left (beige circles). 

Instrument cluster featuring a relative humidity sensor, ultrasonic snow depth sensor, co-located soil moisture and temperature sensors at different depths, and a solar panel to power it all. 

Instrument cluster at  the P303 Upper Met site with ultrasonic snow depth sensor and co-located soil moisture and temperature sensors. 

Instrument cluster at  the P300 Lower Met site with ultrasonic snow depth sensor and co-located soil moisture and temperature sensors. The pole also psupports a solar panel, and an enclosure with a backup power supply and the data logger.

Instruments installed in the P301 meadows include wells and piezometers, at different locations to assess surface and groundwater flows. 

Several clusters of instruments measure the water balance. These clusters each contain soil moisture and temperature sensors, an air temperature sensor, relative humidity sensor, and an ultrasonic snow depth sensor. 

These water balance instruments are clustered at two different elevations, with north, flat, and south facing aspects. Conditions are measured under canopy, at drip edge, and at open canopy. Water balance measurements are also made in the wireless sensor network that stretches along the P301 meadow. 

The eight subcatchments and two integrating catchments in the KREW project have flumes to measures discharge. 

The large KREW flumes are complemented by small flumes for low flow. 

Each of those eight KREW subcatchments also has a plastic-lined settling basin to capture sediment. 

There are two meteorological stations in the Providence catchment - one at the lower elevation range and one near the crest. Each meteorological station has a rain gauge. 

At the upper meteorological station, there is a snow pillow. This snow pillow tracks the weight of snow above it. Combined with the snow depth measurements, the two permit the calculation of amount of water in the snow pack.

Another view of the snow pillow. 

At the San Joaquin Experimental Range (SJER), the SSCZO flux tower sits on a small rise in the oak-pine woodland. This is the lowest site of the flux-tower transect, with the tower installed at 405 m in elevation.  

Fully erected, the SJER tower stands about 29 m tall (~95 ft). 

However, the tower also telescopes down for maintenance. 

Erin Stacy (UC Merced) exchanges the filters on the gas intake. 

The flux tower at Soaproot Saddle stands in a small forest clearing. The tower, approximately 39 m tall (125-130 ft), is surrounded by a mix of Ponderosa pine and oak. Here the WyCEHG (Wyoming) sets out equipment to conduct geophysical surveys in the tower footprint. 

Defensive measures were taken for the Soaproot Saddle tower in advance of a prescribed burn. The Clarence Burn burned up to a nearby firebreak in January 2014, but did not burn the area immediately around the tower 

Matt Meadows (Field Manager, UC Merced) begins the climb for routine tower maintenance in a late January storm, 2014. 

Pete Hartsough (collaborator, UC Davis) stands next to the Soaproot tower, September 2013, with core tubes in hand. A large drilling unit cored soil and saprolite to a depth of ~4 m on most attempts at this site. 

The P301 tower is the tallest of the four towers at 50 m (160 ft), plus a lightning rod. It stands near the top of the Providence catchments at 2015 m in elevation. 

The P301 tower near the end of the 2014 winter. 

Matt Meadows (Field Manager, UC Merced) shows off the filter intakes at the top of the P301 tower.