Quantifying the role of atmospheric rivers in the interior western United States

Royal Meteorological Society (RMS) | July 13th, 2012

Atmospheric rivers (ARs) have increasingly been recognized for their contribution to high-impact weather and climate variability. A recent investigation based on observat

Atmospheric rivers (ARs) have increasingly been recognized for their contribution to high-impact weather and climate variability. A recent investigation based on observations located primarily in lowland valleys and basins of the western United States suggests that 10 – 50% of the total cool season (November to April) precipitation between water years 1998 and 2008 occurred on the day of and day following AR landfall (hereafter the AR fraction), as identified using  Special Sensor Microwave Imager data. However, these results are based only on ARs crossing the North American west coast between 32.5◦N and 52.5◦N, which excludes those crossing the west coast of the Baja Peninsula. Here, we identify ARs in the ERA-Interim reanalysis and examine the AR fraction at high-elevation observational sites and in the NOAA/CPC Unified Daily Precipitation Analysis. At high-elevation snowpack telemetry sites, we find good agreement with the AR fraction obtained previously for valley and basin locations. We also show that including ARs crossing the west coast of the Baja Peninsula (as far south as 24◦N) substantially increases the AR fraction over the southwestern United States

Racanelli Decision: Detailed summary of the decision

Department of Justice (DOJ) | November 16th, 2007

At their meeting on October 25, 2007, the Delta Vision Blue Ribbon Task Force members asked for a summary of United States v. State Water Resources Control Board (1986) 1

At their meeting on October 25, 2007, the Delta Vision Blue Ribbon Task Force members asked for a summary of United States v. State Water Resources Control Board (1986) 182 Cal.App.3d 82, commonly referred to as the “Racanelli Decision,” after the appellate judge who wrote the opinion. We repeat the Court’s own very short summary of the case, followed by a more detailed summary of the decision.

Rain Making

Scientific American | August 11th, 1894

I SHALL ask your attention this evening to the scientific principles which are involved in the condensation of atmospheric vapor, and to some of the attempts which have

I SHALL ask your attention this evening to the scientific principles which are involved in the condensation of atmospheric vapor, and to some of the attempts which have been made to produce this condensation by artificial means. Since the change from atmospheric vapor to water involves a change of the physical state of the same substance from a gas to a liquid.

Rainfall intensification amplifies exposure of American Southwest to conditions that trigger postfire debris flows

Nature Portfolio (Springer Nature) | June 7th, 2024

Rapid decline of California’s native inland fishes: a status assessment

University of California, Davis (UC Davis) | November 1st, 2010

Degradation of freshwater ecosystems is a global crisis best understood through intensive study of well-studied regional faunas. A quantitative protocol was used

Degradation of freshwater ecosystems is a global crisis best understood through intensive study of well-studied regional faunas. A quantitative protocol was used to determine conservation status of all 129 freshwater fishes native to California. Seven (5%) are extinct; 34 (26%) qualified for listing as endangered or threatened species; 32 (25%) were rated as imperiled, qualifying as California Species of Special Concern, with potential for listing; 34 (26%) rated being on a watch list and 22 (17%) were found to be relatively secure. Of 31 species officially listed under federal and state endangered species acts, 17 (55%) clearly qualified for listing under our criteria and 12 (39%) were rated as species of special concern. Conversely, of 34 extant species with the lowest ratings under our criteria, only 17 (50%) were officially listed. Climate change, area occupied and anthropogenic threats had the largest negative impact on status. Of the 15 categories of anthropogenic threats analyzed, those most likely to diminish status were alien species, agriculture and dams. Overall, 83% of California’s freshwater fishes are extinct, endangered, or in decline, a 16% increase since 1995 and a 21% increase since 1989. The decline seen in California’s inland fishes is probably typical of declines in areas that are less well documented, indicating a strong need for better methods of conservation of freshwater ecosystems.

Rapid emergence of climate change in environmental drivers of marine ecosystems

Nature Portfolio (Springer Nature) | March 7th, 2017

Climate change is expected to modify ecological responses in the ocean, with the potential for important effects on the ecosystem services provided to humankind

Climate change is expected to modify ecological responses in the ocean, with the potential for important effects on the ecosystem services provided to humankind. Here we address the question of how rapidly multiple drivers of marine ecosystem change develop in the future ocean. By analysing an ensemble of models we find that, within the next 15 years, the climate change-driven trends in multiple ecosystem drivers emerge from the background of natural variability in 55% of the ocean and propagate rapidly to encompass 86% of the ocean by 2050 under a ‘business-as-usual’ scenario. However, we also demonstrate that the exposure of marine ecosystems to climate change-induced stress can be drastically reduced via climate mitigation measures; with mitigation, the proportion of ocean susceptible to multiple drivers within the next 15 years is reduced to 34%. Mitigation slows the pace at which multiple drivers emerge, allowing an additional 20 years for adaptation in marine ecological and socio-economic systems alike.

Rapid groundwater decline and some cases of recovery in aquifers globally

Nature Portfolio (Springer Nature) | January 24th, 2024

Rapid progression of ocean acidification in the California current system

American Association for the Advancement of Science (AAAS) | June 14th, 2012

Nearshore waters of the California Current System (California CS) already today have a low carbonate saturation state, making them particularly susceptible to o

Nearshore waters of the California Current System (California CS) already today have a low carbonate saturation state, making them particularly susceptible to ocean acidification. Here, we use eddy-resolving model simulations to study the potential development of ocean acidification in this system up to 2050 under the SRES A2 and B1 scenarios. In both scenarios, the saturation state of aragonite Ωaragis projected to drop rapidly, with much of the nearshore regions developing summer-long undersaturation in the top 60 m within the next 30 years. By the year 2050, waters with Ωarag above 1.5 have largely disappeared and more than half of the waters are undersaturated year-round. Habitats along the seafloor become exposed to year-round undersaturation within the next 20 to 30 years. This has potentially major implications for the rich and diverse ecosystem that characterizes the California CS.

Rapid subsidence over oil fields measured by SAR interferometry: Geophysical Research Letters

American Geophysical Union (AGU) | September 1st, 1998

The Lost Hills and Belridge oilfields are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of la

The Lost Hills and Belridge oilfields are in the San Joaquin Valley, California. The major oil reservoir is high porosity and low permeability diatomite. Extraction of large volumes from shallow depths causes reduction in pore pressure and subsequent compaction, forming a surface sub- sidence bowl. We measure this subsidence from space using interferometric analysis of SAR (Synthetic Aperture Radar) data collected by the European Space Agency Remote Sensing Satellites (ERS-1 and ERS-2). Maximum subsidence rates are as high as 40 mm in 35 days or > 400 mm/yr, measured from interferograms with time separations ranging from one day to 26 months. The 8- and 26-month inter-ferograms contain areas where the subsidence gradient exceeds the measurement possible with ERS SAR, but shows increased detail in areas of less rapid subsidence. Synoptic mapping of subsidence distribution from satellite data powerfully complements ground-based techniques, permits measurements where access is difficult, and aids identification of underlying causes

Rapid vegetation redistribution in Southern California during the early 2000s drought

American Geophysical Union (AGU) | August 31st, 2012

Climate change in semi-arid, midlatitude mountain environments is expected to shift the spatial patterns of temperature, water availability, and vegetation upslope. Veg

Climate change in semi-arid, midlatitude mountain environments is expected to shift the spatial patterns of temperature, water availability, and vegetation upslope. Vegetation growing near its low-elevation range limit may prove especially vulnerable to mortality and decline. We investigated the altitudinal pattern of conifer mortality that occurred from 2002 to 2004 in Southern California’s San Jacinto Mountains. We found that conifer mortality was focused in the lower portion of the midmontane conifer range, which drove the midmontane conifer distribution upslope. We investigated past reports of conifer mortality in Southern California by searching historical newspaper accounts. We found evidence of previous episodes of conifer mortality that coincided with past droughts, and which may have caused vegetation redistribution in the past. We interpret the early2000s mortality and associated vegetation redistribution as a response to natural decadal tocentennial climate variability. Moreover, we hypothesize this response mode will dominatethe early impact of global climate change on semi-arid forest, which, in turn, may complicate efforts to distinguish between ecological changes attributable to natural climate variability and those attributable to global climate change.