CW3E Publication Notice: The Role of Atmospheric Rivers in Extratropical and Polar Hydroclimate

CW3E Publication Notice

The Role of Atmospheric Rivers in Extratropical and Polar Hydroclimate

June 28, 2018

Deanna Nash (UC Santa Barbara) and CW3E collaborators Bin Guan (UCLA), Duane Waliser (NASA/JPL), along with CW3E director Marty Ralph and Hengchun Ye (Cal State LA) recently published a paper in Journal of Geophysical Research: Atmospheres, titled The Role of Atmospheric Rivers in Extratropical and Polar Hydroclimate.

Atmospheric Rivers (ARs) are narrow, long, transient, water vapor rich corridors of the atmosphere that are responsible for over 90% of the poleward water vapor transport in and across mid-latitudes. However, the role of ARs in modulating extratropical and polar hydroclimate features (e.g. water vapor content, precipitation) has not been fully studied, even though moistening of the polar atmosphere is both a key result of, and amplifier of, arctic warming and sea ice melt, and precipitation is key to the surface mass balance of polar sea ice and ice sheets. This study uses the MERRA2 reanalysis to characterize the roles of AR water vapor transport on the column-integrated atmospheric water vapor budget in the extratropical and polar regions of both hemispheres.

Meridional water vapor transport by ARs across a given latitude (examined for 40°, 50°, 60°, and 70°) is strongly related to variations in area-average (i.e. over the “cap” poleward of the given latitude) total water vapor storage and precipitation poleward of that latitude. For the climatological annual cycle, both AR transport (i.e., non-local sources) and total evaporation (i.e., local sources) are most correlated with total precipitation, although with slightly different phases. However, for monthly anomalies, the water budget at higher latitudes is largely dominated by the relationship between AR transport and precipitation. For pentad and daily anomalies, AR transport is related to both precipitation and water vapor storage variations. These results demonstrate the important role of episodic, extreme water vapor transports by ARs in modulating extratropical and polar hydroclimate.

Figure 1 from Nash et al. 2018. a) A schematic of the atmospheric water budget for a region poleward of a given latitude (e.g. 60ºN). The red arrows indicate flux of integrated water vapor transport (IVT), the majority of which is AR-related in the mid to high latitudes. The green arrows indicate the surface evaporation (E) of water poleward of a given latitude, and the clouds and rain indicate the loss of water vapor when it condenses and falls as precipitation (P). All these terms combine into equation 1 where the change in water vapor storage (∂IWV/∂t) is equal to the evaporation minus the precipitation in the region plus the flux of IVT into that region. b) A schematic showing a top down view of IVT and AR-IVT flux at 60°N. The majority of IVT and AR-IVT enter the Arctic via the red line regions (i.e. the AR-IVT Atlantic and Pacific Pathways).

Figure 10 from Nash et al., 2018. Correlation Ellipses between IVT and each variable (solid ellipse), and AR-IVT and each variable (translucent ellipse). The color of each ellipse indicates the correlation coefficient. The width of each ellipse is 1- |r|, and the orientation (downward/upward) indicates the sign of the relationship (positive/negative). The length of each ellipse is 1 (such that a circle would indicate zero correlation).

This research was supported by the NASA Energy and Water cycle Study (NEWS) program, NASA NCA, and NASA MIRO grant. Deanna Nash’s contribution to this study was made possible by NASA Jet Propulsion Laboratory’s Year-Round Internship Program during her graduate studies at California State University, Los Angeles. Please contact Duane Waliser at duane.waliser@jpl.nasa.gov with inquiries.

Nash, D., Waliser, D., Guan, B., Ye, H., & Ralph, M. (2018). The Role of Atmospheric Rivers in Extratropical and Polar Hydroclimate. Journal of Geophysical Research: Atmospheres, 123. https://doi.org/10.1029/2017JD028130

2nd International Atmospheric Rivers Conference, June 2-28, 2018

2nd International Atmospheric Rivers Conference, June 25-28, 2018

June 22, 2018

The Center for Western Weather and Water Extremes (CW3E), at the Scripps Institution of Oceanography (SIO), UC San Diego, is hosting the 2nd International Atmospheric Rivers Conference (IARC) from June 25-28, 2018. Ths conference is organized by an international committee, with co-chairs from NASA’s Jet Propulsion Laboratory, the US Army Corps of Engineers, CW3E, and the University of Lisbon.

The conference is located at the seaside Robert Paine Scripps Forum for Science, Society, and the Environment on SIO’s campus. Over 100 experts across multiple fields are coming together to advance the state of the science and explore needs for new information. Fifteen student scholarships were given to students coming from locations such as India, Chile, and across the U.S. There will be extensive opportunity for interaction during the conference and after. A cocktail hour and dinner, included with registration, will be provided on Tuesday, June 26.

The agenda and other information can be found on the IARC website. Traditional oral and poster sessions are combined with panel discussions and breakout sessions. Sessions will be focused on various topics including: Winter 2016-2017; Airborne observations of atmospheric rivers (ARs); Subseasonal to seasonal forecasting of ARs; Applications and communications; AR Tracking; Regional perspectives on ARs; AR dynamics; AR microphysics, aerosols, and chemistry; Weather forecasting of ARs; ARs and Hydrologic Impacts; ARs and climate variability: past, present, and future; and Emerging directions.

Immediately after the conference, CW3E is also sponsoring a student forecasting workshop to be held June 29-30, with exercises planned on decision maker communication and forecasting for airborne field campaigns. Students will also be able to tour the National Weather Service San Diego offices and participate in a demonstration radiosonde launch from the Scripps Pier.

CW3E Staff Member Attends Russian River Science Forum

CW3E Staff Member Attends Russian River Science Forum

May 03, 2018

CW3E’s Anna Wilson recently attended the Russian River Science Forum, held at the Sonoma County Water Agency on May 1. The Forum was sponsored by the California Land Stewardship Institute, Sonoma County Agricultural Preservation and Open Space District, and Sonoma County Water Agency, and was meant to gather together scientists, conservationists, and stakeholders to discuss research needs and ongoing work being conducted in the watershed. The framework for the forum was research priorities identified by the Russian River Independent Science Review Panel (ISRP). Broadly, these priorities are: aquatic communities; groundwater; streamflow; climate change; water demand and use; geomorphology; and development of a numerical model of the watershed.

Presentations included ongoing relevant weather and climate research conducted by CW3E and partners (Anna Wilson, CW3E), local research applications (Jay Jasperse, Sonoma County Water Agency; Karen Gaffney, Sonoma County Agricultural Preservation and Open Space District), monitoring the effects of the 2017 wildfires (Jonathan Perkins, US Geological Survey; Virginia Mahacek, Sonoma County Office of Recovery and Resilience), and restoration design (Neil Lassettre, Sonoma County Water Agency). There was time for discussion regarding progress on the recommendations from the ISRP, and on future collaborations between interested researchers and stakeholders. CW3E looks forward to further partnerships towards advancing science objectives in the Russian River watershed and assisting in the development of science-based, resilient, and effective watershed management strategies.

CW3E Graduate Student Named AGU Voices for Science Advocate

CW3E Graduate Student Named AGU Voices for Science Advocate

May 21, 2018

Tashiana Osborne, a Ph.D. student within CW3E, was recently selected to become 1 of 30 American Geophysical Union (AGU) Voices for Science Advocates across the US. According to the AGU, their new program, Voices for Science, was ‘designed to create a network of skilled and dedicated scientists who are ready to share their science with a variety of important audiences’, including lawmakers, the media, community members, children, and others.

Osborne and other Advocates were flown to Washington, D.C. in April to complete a skill-building training in science communication and policy. During this training, Advocates created action plans, committing to create, contribute to, and/or engage peers in relevant activities throughout the year. AGU will reunite Advocates in Washington, D.C. for the December 2018 AGU Fall Meeting, where Advocates will share highlights from the year and participate in additional activities.

AGU emphasizes, ‘By participating in the Voices for Science program, the Advocates are helping to build public support for Earth and space science, protect critical science funding, and advance federal support for science policy. We look forward to sharing their success stories and lessons learned, and we hope they will serve as an inspiration for other AGU members to embark on their own science advocacy journeys.’

Voices for Science feature in AGU’s Earth & Space Science News (EOS): https://eos.org/agu-news/new-program-enables-scientists-to-be-voices-for-science

AGU Voices for Science Advocates (within the Communication track) after practicing techniques to communicate research with various audiences (Photo Credit: AGU)

International Atmospheric Rivers Conference 2018

International Atmospheric Rivers Conference 2018 – Abstract Submission and Registration Open Now! Abstracts Due April 2, 2018

The Center for Western Weather and Water Extremes (CW3E), at Scripps Institution of Oceanography (SIO), UC San Diego will be hosting the 2nd International Atmospheric Rivers Conference (IARC) from June 25-28, 2018. The conference is organized by an international committee, with co-chairs from NASA’s Jet Propulsion Laboratory, the US Army Corps of Engineers in Seattle, CW3E, and Instituto Dom Luiz at the University of Lisbon.

 

The conference will be located at the beautiful Robert Paine Scripps Forum for Science, Society and the Environment on SIO’s campus. The conference will bring together experts across multiple fields to advance the state of the science and explore needs for new information. Traditional oral and poster sessions will be combined with panel discussions. Cutting-edge research with global and regional perspectives on atmospheric river (AR) science will be presented. Topics include: field observations and remote sensing, AR identification and tracking, physical processes, interactions between atmospheric transport and chemistry, forecasting capabilities, ARs and climate change, and emerging directions – as well as many others.

 

In 2016, CW3E hosted the first ever IARC, drawing over 100 participants from all over the globe including Australia, South America, Europe, Asia and Africa (Ralph et al., 2017). Participants came from all different disciplines and perspectives, from applications, engineering, water management, to researchers using modeling, theory, and observed data to investigate these phenomena. ARs have emerged as a hugely useful conceptual model to focus hydrologists and atmospheric scientists on the transport mechanisms and impacts of precipitation extremes caused by AR landfall, and we look forward to hosting an engaging, inspiring, four-day conference.

 

Abstract submission deadline is April 2, 2018. Student scholarships, which waive the registration fee, are available. Students are strongly encouraged to apply. The student scholarship application deadline is also April 2, 2018.

 

For more information regarding this conference, please visit: http://cw3e.ucsd.edu/iarc2018/. If you have further questions, please contact Dr. Anna Wilson or Dr. Alexandre Ramos.

CW3E AR Update: 20 March 2018 Outlook

CW3E AR Update: 20 March Outlook

March 20, 2018

Click here for a pdf of this information.

Update on Atmospheric River Forecast to Impact California This Week

  • The terminus of the atmospheric river plume is approaching coastal CA and precipitation will begin today
  • Models are suggesting potentially strong (IVT >750 kg m-1 s-1) AR conditions over San Luis Obispo and Santa Barbara Counties
  • Locations further south may experience moderate strength AR conditions (IVT >500 kg m-1 s-1)
  • AR conditions are forecast to peak over portions of SoCal between Midnight and 11 AM PDT on Thursday, 22 March 2018
  • As much as 10 inches of precipitation may fall over the higher elevations of Santa Barbara and Ventura Counties
  • The National Weather Service has issued numerous Flash Flood Watches and Winter Weather Warnings in California

SSMI/SSMIS/AMSR2-derived Integrated Water Vapor (IWV)

Valid 0000 UTC 18 March – 1600 UTC 20 March 2018

Images from CIMSS/Univ. of Wisconsin

Click IVT or IWV image to see loop of 0-72 hour GFS forecast

Valid 1200 UTC 20 March – 1200 UTC 23 March 2018

 

 

 

 

 

 

 

 

 

 

Summary provided by C. Hecht, F.M. Ralph, J. Rutz, and B. Kawzenuk; 1 PM PT Tuesday 20 March 2018

*Outlook products are considered experimental

CW3E AR Update: 16 March 2018 Outlook

CW3E AR Update: 16 March Outlook

March 16, 2018

Click here for a pdf of this information.

Update on Atmospheric River Forecast to Impact California Next Week

  • Several changes have occurred in the forecast for the AR that may impact CA later next Week
  • GFS Ensemble members have started to converge on coastal AR conditions
  • While there is more agreement between ensemble members, there is still considerable uncertainty in onset, duration, and magnitude of AR conditions

Click IVT or IWV image to see loop of 18-180 hour GFS forecast

Valid 0600 UTC 17 March – 0000 UTC 24 March 2018

 

 

 

 

 

 

 

Summary provided by C. Hecht, F.M. Ralph, and B. Kawzenuk; 3 PM PT Friday 16 March 2018

*Outlook products are considered experimental

CW3E AR Update: 15 March 2018 Outlook

CW3E AR Update: 15 March Outlook

March 15, 2018

Click here for a pdf of this information.

A potentially moderate strength atmospheric river is forecast to impact Southern California

  • An AR is currently forecast to impact Southern California on 21 and 22 March 2018
  • Some GFS ensemble members are indicating that this AR could be moderate strength (IVT >500 m-1 s-1)
  • There is currently large uncertainty pertaining to the magnitude and duration of this event
  • CW3E’s high resolution West-WRF model suggests this event is capable of producing 2-4 inches of precipitation over portions of Southern California

Click IVT or IWV image to see loop of 48-180 hour GFS forecast

Valid 0600 UTC 17 March – 1800 UTC 22 March 2018

 

 

 

 

 

Summary provided by C. Hecht, F.M. Ralph, B. Kawzenuk, and J. Cordeira; 12:30 PM PT Thursday 15 March 2018

*Outlook products are considered experimental

CW3E AR Update: 27 January 2017 Outlook

CW3E AR Update: 27 January Outlook

January 27, 2018

Click here for a pdf of this information.

Multiple ARs Currently Impacting and Forecast to Impact the West Coast this Weekend

  • An AR is currently impacting the West Coast (Referred to as AR 1)
  • Two Air Force C-130s and a NOAA G-IV collected observations within this AR on 26 January
  • A second (Referred to as AR 2) AR developed from a mesoscale frontal wave within the first AR and is forecast to make landfall at ~6 UTC on the 28th (10 PM PST on the 27th)
  • Over 10 inches of precipitation may fall over the Higher elevations of the Olympic mountains and Vancouver Island due to the two ARs

Click IVT or IWV image to see loop of 0-180 hour GFS forecast

Valid 1200 UTC 27 January – 0000 UTC 04 February 2018

 

 

 

 

 

 

Summary provided by C. Hecht, F.M. Ralph, A. Wilson; 2 PM PT Saturday 27 January 2018

*Outlook products are considered experimental

CW3E AR Update: 8-10 January 2018 Post Event Summary

CW3E AR Update: 8-10 January 2018 Post Event Summary

January 8, 2018

Click here for a pdf of this information.

Atmospheric river conditions brought widespread precipitation throughout California

  • A low pressure system developed off the CA coast on 7 January and interacted with tropical moisture to produce heavy precipitation over nearly all of CA
  • Nearly all of CA experienced AR conditions (IVT >250 kg m-1 s-1 and IWV >20 mm) for ~24 hours
  • The highest precipitation amounts were observed over the Coastal and Transverse Ranges, with some locations receiving over 200 mm of precipitation, making this and R-Cat 1 event

Click IVT or IWV image to see loop of GFS analysis

Valid 0000 UTC 5 January – 0000 UTC 10 January 2018

SSMI/SSMIS/ARMSR2-Derived Integrated Water Vapor (IWV)

Valid 0000 UTC 7 January – 1200 UTC 10 January 2018

NEXRAD Radar Reflectivity

Valid 0000 UTC 8 January – 1200 UTC 10 January 2018

Precipitation began over California around 400 UTC 8 January and lasted until early 10 January



 

 

 

 

 

 

 

 

Summary provided by B. Kawzenuk and F.M. Ralph; 12 PM PT Thursday 11 January 2018