Cooperative Institute for Research in Environmental Sciences



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The influence of the Rocky Mountains on the ocean's Meridional Overturning Circulation

The influence of the Rocky Mountains on the ocean's Meridional Overturning Circulation

Dr. Elizabeth Maroon
Postdoctoral Researcher
Cooperative Institute for Research in Environmental Sciences (CIRES)
University of Colorado

Title: "The influence of the Rocky Mountains on the ocean's Meridional Overturning Circulation”

Abstract:
The general circulation of the ocean features a strong Meridional Overturning Circulation (MOC) in the North Atlantic that has no equivalent in the North Pacific. Several hypotheses have been suggested for this asymmetry, including differences in ocean basin width, the southern extent of Africa, and the poleward extent of the Atlantic. In this study, we test Warren’s (1983) hypothesis that a vigorous MOC exists in the North Atlantic and not the North Pacific because the gyre circulation in the North Atlantic is more efficient in transporting salty water northward poleward than is the gyre circulation in the North Pacific; these gyre circulation differences were hypothesized to stem from wind stress differences that are due to a stationary wave, generated by the Rocky Mountain Cordillera. We first perform a control integration of a modified version of the coarse resolution coupled climate model from GFDL (CM2Mc see Galbraith et al., 2011), which features reasonably realistic circulation in the North Pacific and Atlantic. Branching off the control simulation, we then flatten the Rocky Mountains. Within a few decades of flattening, deep convection and a MOC appear in the North Pacific, and the Atlantic MOC is reduced. After a few centuries, the new equilibrium has a 25 Sv MOC in the Pacific, deep convection in the northwest Pacific, and a reduced Atlantic MOC. We then perform a second simulation to examine whether these ocean circulation changes are due to changes in the wind stress or due to changes in river runoff from flattening the Rockies. In this simulation, we retain the Rockies orography but artificially re-route North American runoff that would have flowed to the Pacific to instead flow to the Atlantic. The resulting MOC changes are very similar to those in the flattened Rockies experiment. The results from these simulations suggest that the impact of the Rockies on the global ocean MOC is primarily through their impact on hydrology rather than on surface winds.

date

Wednesday, May 3, 2017
11:00am

location

East Campus, RL-2, room 155
Seminar

contact

2017-05-03
 
 
 
 
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WWA/NIDIS Webinar

WWA/NIDIS Webinar

WWA/NIDIS Webinar
Presented by the Western Water Assessment and National Integrated Drought Information System

Thursday, May 11, 2017
11:00 am – 12:00 pm MDT

To connect, please follow this link: http://cirescolorado.adobeconnect.com/eddi-5-11-2017/

To connect by phone, please use the following numbers:

            Call in:  877-995-0511

            Code:  4482367

Evaporative Demand Drought Index (EDDI): Tracking the “atmospheric demand” side of drought for monitoring and early warning

Imtiaz Rangwala, Mike Hobbins, and Jeff Lukas for the EDDI Team*

EDDI is a drought indicator that examines changes in the atmospheric evaporative demand to indicate the spatial extent and severity of drought over multiple timescales. In this webinar, we will describe the physical basis of EDDI and summarize some early results that demonstrate its potential and added value in early warning and ongoing monitoring of drought. We will also describe the various resources available from the EDDI tool, and share insights gained from our engagement with a diverse set of stakeholders on its effectiveness and usability.

*Joe Barsugli1,2,4, Candida Dewes1,2, Mike Hobbins1,2, Justin Huntington3, Jeff Lukas4, Daniel McEvoy3, Charles Morton3, Imtiaz Rangwala1,2,4, Andrea Ray1, and Heather Yocum1,2

1.    NOAA/ESRL Physical Sciences Division
2.    University of Colorado/Cooperative Institute for Research in Environmental Sciences
3.    Desert Research Institute
4.    Western Water Assessment
 

date

Thursday, May 11, 2017
11:00am to 12:00pm
2017-05-11
 
 
 
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CIRES Rendezvous 2017

CIRES Rendezvous 2017

The CIRES Members' Council is pleased to announce the 10th annual CIRES Rendezvous and CIRES 50th Anniversary. This institute-wide symposium will take place on Thursday, May 18th, 2017 with the aim of bringing awareness to the depth, breadth, and quality of the pacesetting science being done at CIRES. We hope to encourage collaborations that might result in new interdisciplinary research, and to facilitate connections among our many innovative scientists, science support staff, and administrative staff.

This half-day event includes an entire afternoon devoted to CIRES science and poster presentations; we encourage you to participate and present your research here. We are happy for you to present posters that may have been used previously at AMS, AGU, ACS, or other meetings. Of course, you are also free to develop a new poster or present new work.

date

Thursday, May 18, 2017
1:00pm

location

resources

Rendezvous
2017-05-18
 
 
 
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WWA/NIDIS Webinar: Decision making in the face of drought by western range livestock producers

WWA/NIDIS Webinar: Decision making in the face of drought by western range livestock producers

William R. Travis and Trisha Shrum
Western Water Assessment and Earth Lab
University of Colorado Boulder

Ranchers make a large number of time-sensitive decisions each year and can vary their choices in the face of drought throughout the production cycle.  Ranchers’ drought decisions may also be affected by USDA’s new Pasture Rangeland and Forest insurance program, a rainfall-index product meant to compensate for added feed costs during drought.

We use multiple ranch decision models to simulate the effectiveness of drought adaptations under different rainfall and forage conditions, and with or without range insurance.  The results include annual profit and end-of-year net worth after drought responses on a typical Great Plains-Rocky Mountain cow/calf ranch. The simulations illuminate the role of adaptation costs, insurance, and drought early warning in the decision-making process. We also examine alternative drought indices and the effect of drought on cattle markets, both of which feed back to rancher decisions.

This webinar will:

Review resource decisions in the face of drought, focusing on range livestock production
Examine decision models available to ranchers
Demonstrate new ranching decision models developed especially for drought, incorporating climate information and the role of range insurance
Discuss next steps in the use of drought early warning in range and other resource sectors

date

Wednesday, May 31, 2017
10:00am
2017-05-31