Characterization of five unconventional diatomaceous (opal-A) reservoirs, Monterey Formation, San Joaquin Valley, California

AAPG Bulletin ◽  
2021 ◽  
Vol 105 (2) ◽  
pp. 391-436
Author(s):  
David K. Larue ◽  
Christian Hager ◽  
Thomas Meffifield ◽  
Gena M. Evola ◽  
David Crane ◽  
...  
Keyword(s):  
San Joaquin Valley ◽  
Monterey Formation

scholarly journals Satellite mapping of PM<sub>2.5</sub> episodes in the wintertime San Joaquin Valley: a “static” model using column water vapor

2020 ◽  
Vol 20 (7) ◽  
pp. 4379-4397 ◽  
Author(s):  
Robert B. Chatfield ◽  
Meytar Sorek-Hamer ◽  
Robert F. Esswein ◽  
Alexei Lyapustin
Keyword(s):  
Water Vapor ◽  
Mixed Layer ◽  
Atmospheric Correction ◽  
Vertical Mixing ◽  
San Joaquin Valley ◽  
Winter Period ◽  
Statistical Regression ◽  
Simple Method ◽  
Near Surface

Abstract. The use of satellite aerosol optical thickness (AOT) from imaging spectrometers has been successful in quantifying and mapping high-PM2.5 (particulate matter with a mass <2.5 µm diameter) episodes for pollution abatement and health studies. However, some regions have high PM2.5 but poor estimation success. The challenges in using AOT from imaging spectrometers to characterize PM2.5 worldwide was especially evident in the wintertime San Joaquin Valley (SJV). The SJV's attendant difficulties of high-albedo surfaces and very shallow, variable vertical mixing also occur in other significantly polluted regions around the world. We report on more accurate PM2.5 maps (where cloudiness permits) for the whole winter period in the SJV (19 November 2012–18 February 2013). Intensive measurements by including NASA aircraft were made for several weeks in that winter, the DISCOVER-AQ (Deriving Information on Surface Conditions from COlumn and VERtically Resolved Observations Relevant to Air Quality) California mission. We found success with a relatively simple method based on calibration and checking with surface monitors and a characterization of vertical mixing, and incorporating specific understanding of the region's climatology. We estimate PM2.5 to within ∼7 µg m−3 root mean square error (RMSE) and with R values of ∼0.9, based on remotely sensed multi-angle implementation of atmospheric correction (MAIAC) observations, and certain further work will improve that accuracy. Mapping is at 1 km resolution. This allows a time sequence of mapped aerosols at 1 km for cloud-free days. We describe our technique as a “static estimation.” Estimation procedures like this one, not dependent on well-mapped source strengths or on transport error, should help full source-driven simulations by deconstructing processes. They also provide a rapid method to create a long-term climatology. Essential features of the technique are (a) daily calibration of the AOT to PM2.5 using available surface monitors, and (b) characterization of mixed layer dilution using column water vapor (CWV, otherwise “precipitable water”). We noted that on multi-day timescales both water vapor and particles share near-surface sources and both fall to very low values with altitude; indeed, both are largely removed by precipitation. The existence of layers of H2O or aerosol not within the mixed layer adds complexity, but mixed-effects statistical regression captures essential proportionality of PM2.5 and the ratio variable (AOT ∕ CWV). Accuracy is much higher than previous statistical models and can be extended to the whole Aqua satellite data record. The maps and time series we show suggest a repeated pattern for large valleys like the SJV – progressive stabilization of the mixing height after frontal passages: PM2.5 is somewhat more determined by day-by-day changes in mixing than it is by the progressive accumulation of pollutants (revealed as increasing AOT).

scholarly journals Identification and Characterization of Bacteria in a Selenium-Contaminated Hypersaline Evaporation Pond

2001 ◽  
Vol 67 (9) ◽  
pp. 3785-3794 ◽  
Author(s):  
M. P. de Souza ◽  
A. Amini ◽  
M. A. Dojka ◽  
I. J. Pickering ◽  
S. C. Dawson ◽  
...  
Keyword(s):  
Health Hazard ◽  
Drainage Water ◽  
San Joaquin Valley ◽  
Agricultural Drainage ◽  
Bacterial Isolates ◽  
Evaporation Ponds ◽  
Uncultured Bacteria ◽  
X Ray Absorption ◽  
Identification And Characterization

ABSTRACT Solar evaporation ponds are commonly used to reduce the volume of seleniferous agricultural drainage water in the San Joaquin Valley, Calif. These hypersaline ponds pose an environmental health hazard because they are heavily contaminated with selenium (Se), mainly in the form of selenate. Se in the ponds may be removed by microbial Se volatilization, a bioremediation process whereby toxic, bioavailable selenate is converted to relatively nontoxic dimethylselenide gas. In order to identify microbes that may be used for Se bioremediation, a 16S ribosomal DNA phylogenetic analysis of an aerobic hypersaline pond in the San Joaquin Valley showed that a previously unaffiliated group of uncultured bacteria (belonging to the orderCytophagales) was dominant, followed by a group of cultured γ-Proteobacteria which was closely related to Halomonas species. Se K-edge X-ray absorption spectroscopy of selenate-treated bacterial isolates showed that they accumulated a mixture of predominantly selenate and a selenomethionine-like species, consistent with the idea that selenate was assimilated via the S assimilation pathway. One of these bacterial isolates (Halomonas-like strain MPD-51) was the best candidate for the bioremediation of hypersaline evaporation ponds contaminated with high Se concentrations because it tolerated 2 M selenate and 32.5% NaCl, grew rapidly in media containing selenate, and accumulated and volatilized Se at high rates (1.65 μg of Se g of protein−1 h−1), compared to other cultured bacterial isolates.

scholarly journals Hydrogeologic characterization of the Modesto Area, San Joaquin Valley, California

2004 ◽  
Author(s):  
Karen R. Burow ◽  
Jennifer L. Shelton ◽  
Joseph A. Hevesi ◽  
Gary S. Weissmann
Keyword(s):  
San Joaquin Valley
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