Describes application and function of a the LIAISON, a new Picarro universal interface for high throughput analysis.

While stable isotope techniques have been previously applied to partition evapotranspiration (ET) fluxes in crops, it has only recently become possible to take in situ, long-term, continuous (every 10 seconds) measurements of stable water vapor isotopologues. A Picarro water vapor isotope analyzer (L1115-_i) based on cavity ringdown spectroscopy (CRDS) was recently…

The regulation of Earth’s climate and its ability to sustain life are critically linked to water as it exists in all three of its phases (gas, liquid, and solid). Earth’s water cycle, its movement between the hydrosphere, biosphere, and the atmosphere, and how it undergoes phase changes, is incredibly complex. While we continue to gain insight into the water cycle, there remains…

The quantification of fugitive methane emissions from extended sources such as landfills is problematic due to the high temporal variability and spatial heterogeneity of the emission. Additionally, the relationship between the emission rate and the gas concentration at a given location is dependent on the meteorological conditions and local topography, preventing accurate quantification of…

Cavity Ring-Down spectroscopy is becoming a gold standard for atmospheric monitoring. High sensitivity and precision coupled with low drift characteristics ensure optimal operation even in remote field stations or on aircraft and ships. However, current platforms have been limited to two or three species simultaneous observation. Research and development at Picarro have been focused on…

Hydrothermal fluids from two vent sites along the East Scotia Ridge, E2 and E9, were analyzed for their hydrogen and oxygen isotopic values using a Picarro L1115-i CRDS. The fluids display varying salinity, sulfate and hydrogen sulfide content. None of the samples analyzed in this work showed any signs of spectroscopic interference. Isotopic values of the fluids were combined with…

The world’s first continuous flow isotopic TIC/DOC-CRDS measurements are reported here with remarkable achieved precisions. A measurement precision of the isotopic ratio in the range of 0.2 ‰ to 0.4 ‰ was achieved in minutes of measurement time. Such precision readily distinguishes the isotopic DIC and DOC signatures from a set of three different streamwater samples collected from various…

Describes a field campaign wherein a Picarro water isotope analyzer was used to measure isotopes in water vapor over a corn field in China for the purpose of studying evapotranspiration. The Picarro sampled vapor along with a cold trap sampling system and the real-time Picarro data was compared to offline analysis of the trapped vapor.

The recent development of a field deployable water isotope analyzer using CRDS technology was used to directly measure the vapor isotopes in real time and at multiple heights above the crop canopy. This technique was coupled with additional samples gathered using conventional techniques and a new xylem water extracting apparatus developed by the IAEA.

In a paper published by the Integrated Carbon Observation System (ICOS), the drift performance of 47 Picarro analyzers of 3 different generations were compared (Yver Kowket al, Atmos. Meas. Tech. Discuss., 8, 4219–4272, 2015). The results show that methane drift (the minimum of the Allan standard deviation) was much better in first-generation G1000 analyzers.

High-salinity waters such as Seawater poses an operational and maintenance challenge to the measurements of water stable isotopes via Cavity Ring-Down Spectroscopy. As liquid samples are evaporated in the vaporizer peripheral before being sent to the CRDS analyzer, salt precipitates accumulate in the vaporizer chamber. As a result, the sample-to-sample memory performance degrades over time…

Soil flux chamber measurements are a key tool for determining production and sequestration of direct and indirect greenhouse gases. The Picarro G2508 Cavity Ring-down Spectrometer radically simplifies soil flux analyses by providing simultaneous measurements of five gases: CO2, CH4, N2O, NH3, and H2O, and by ready field deployment. The Picarro Soil Flux Software (SFP) …

With a global warming potential of nearly 300, N2O is a critically important greenhouse gas, contributing about 5 % of the US total GHG  emissions.  Agriculture soil management practices are the dominant source of anthropogenic N2O emissions, contributing nearly 75 % of US N2O emissions.  In urban areas, vehicle tailpipe emissions and waste water treatment plants are…

The necessity for constant monitoring of greenhouse gases (GHGs) is clearly evident now more than ever. Moreover, interpreting and understanding the processes that dictate the production and consumption of these gases will allow for proper management of GHGs in order to mitigate its detrimental climate effects. Presence of oxygen, or lack of it, is the driving force for determining pathways…

Exploration of unconventional natural gas reservoirs such as impermeable shale basins through the use ofhorizontal drilling and hydraulic fracturing has changed the energy landscape in the USA providing a vastnew energy source. The accelerated production of natural gas has triggered a debate concerning thesafety and possible environmental impacts of these operations. This study investigates…

A novel instrument, based on cavity-ringdown spectroscopy (CRDS), has been developed for trace gas detection. The new instrument utilizes a widely tunable optical parametric oscillator (OPO), which incorporates a zinc–germanium–phosphide (ZGP) crystal that is pumped at 2.8 μm by a 25-Hz Er,Cr:YSGG laser. The resultant mid-IR beam profile is nearly Gaussian, with energies exceeding 200…

Cavity enhanced spectroscopy (CES) methodology provides a much higher degree of sensitivity than that available from conventional absorption spectrometers. The aim of this chapter is to present the fundamentals of the method, and the various modifications and extensions that have been developed. In order to set the stage, the limitations of traditional absorption spectrometers are…

High fluences inside cavity ring-down spectroscopy optical resonators lend themselves to fluorescence or Raman spectroscopy. An instrument at 488 nm was developed to measure extinction, and fluorescence of aerosols. A detection limit of 6 x 10^-9 cm^-1Hz^-1/2 (0.6 Mm^-1Hz^-1/2) was achieved. The fluorescence spectral power collected from a single fluorescent microsphere was 10 to 20 pW/nm.…

An historical overview of laser-based, spectroscopic methods that employ high-finesse optical resonators is presented. The overview begins with the early work in atomic absorption (1962) and optical cavities (1974) that led to the first mirror reflectivity measurements in 1980. This paper concludes with very recent extensions of cavity-enhanced methods for the study of condensed-phase media…

We describe the application of cavity ring-down spectroscopy (CRDS) to the detection of trace levels of ethylene in ambient air in a cold storage room of a fruit packing facility over a several month period. We compare these results with those obtained using gas chromatography (GC), the current gold standard for trace ethylene measurements in post-harvest applications. The CRDS instrument…

Recent measurements of carbon isotopes in carbon dioxide using near-infrared, diode-laser-based cavity ring-down spectroscopy (CRDS) are presented. The CRDS system achieved good precision, often better than 0.2‰, for 4% CO₂ concentrations, and also achieved 0.15–0.25‰ precision in a 78 min measurement time with cryotrap-based pre-concentration of ambient CO₂…

Researchers investigating global climate change need measurements of greenhouse gases with extreme precision and accuracy to enable the development and benchmarking of better climate models. Existing atmospheric monitors based on non-dispersive infrared (NDIR) sensors have known problems – they are non-linear, sensitive to water vapor concentration, and susceptible to drift. Many cannot…

Eleven instruments for the measurement of ambient concentrations of atmospheric ammonia gas (NH₃), based on eight different measurement methods were inter-compared above an intensively managed agricultural field in late summer 2008 in S. Scotland. To test the instruments over a wide range of concentrations, the field was fertilised with urea midway through the experiment, leading…