Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

California’s Central Valley sees big drop in wintertime fog needed for fruit and nut crops

21.05.2014

California’s winter tule fog — hated by drivers, but needed by fruit and nut trees — has declined dramatically over the past three decades, raising a red flag for the state’s multibillion dollar agricultural industry, according to new research.

Crops such as almonds, pistachios, cherries, apricots and peaches go through a necessary winter dormant period brought on and maintained by colder temperatures. Tule fog, a thick ground fog that descends upon the state’s Central Valley between late fall and early spring, helps contribute to this winter chill.


Tule fog drifts through a walnut orchard south of Meridian, along the Sacramento River.

Copyright Anthony Dunn Photography. For reprint permission, go to http://www.adunnphotography.com/


A satellite image shows a thick bank of fog blanketing the Central Valley of California. A new study finds that tule fog, a thick ground fog that descends upon the Central Valley between late fall and early spring, has declined dramatically over the past three decades.

Credit: NASA

“The trees need this dormant time to rest so that they can later develop buds, flowers and fruit during the growing season,” said University of California, Berkeley biometeorologist and study lead author Dennis Baldocchi, whose father grew almonds and walnuts in Antioch and Oakley. “An insufficient rest period impairs the ability of farmers to achieve high quality fruit yields.”

The study, published May 15 in the journal Geophysical Research Letters, a journal of the American Geophysical Union, has implications for the entire country since many of these California crops account for 95 percent of U.S. production, the authors noted.

... more about:
»AGU »Environmental »Geophysical »crops »nut »temperature

The researchers paired NASA and National Oceanic and Atmospheric Administration satellite records with data from a network of University of California weather stations, covering 32 consecutive winters. There was a great deal of variability from year to year, but on average, the researchers found a 46 percent drop in the number of fog days between the first of November and the end of February.

“The year-to-year variability we saw was likely influenced by whether the season was relatively wet or dry,” said Baldocchi, a professor in UC Berkeley’s Department of Environmental Science, Policy and Management. “Generally, when conditions are too dry or too wet, we get less fog. If we’re in a drought, there isn’t enough moisture to condense in the air. During wet years, we need the rain to stop so that the fog can form.”

Other studies have marked the decline in the Central Valley of winter chill – the number of hours between 0 and 7 degrees Celsius (32 and 45 degrees Fahrenheit). The number of hours of winter chill has dropped by several hundred since the 1950s, the study authors noted.

But ambient air temperature alone may not adequately reflect the heat experienced by the crops, said Baldocchi. Direct sunlight can heat the buds so that they are warmer than the surrounding air temperature. As a result, fog is important in shielding the buds from the sun and helping them accumulate winter chill.

Climate forecasts suggest that the accumulation of winter chill will continue to decrease in the Central Valley. Baldocchi said that fruit developers are already trying to develop cultivars that can tolerate less winter chill.

“Farmers may also need to consider adjusting the location of orchards to follow the fog, so to speak,” said Baldocchi. “Some regions along the foothills of the Sierra are candidates, for instance. That type of change is a slow and difficult process, so we need to start thinking about this now.”

The study was co-authored by Eric Waller, a UC Berkeley Ph.D. student in the Department of Environmental Science, Policy and Management. The California Energy Commission supported this research.

###

The American Geophysical Union is dedicated to advancing the Earth and space sciences for the benefit of humanity through its scholarly publications, conferences, and outreach programs. AGU is a not-for-profit, professional, scientific organization representing more than 62,000 members in 144 countries. Join our conversation on FacebookTwitter, YouTube, and other social media channels.

Notes for Journalists

Journalists and public information officers (PIOs) of educational and scientific institutions who have registered with AGU can download a PDF copy of this accepted article by clicking on this link: http://onlinelibrary.wiley.com/doi/10.1002/2014GL060018/abstract

Or, you may order a copy of the final paper by emailing your request to Nanci Bompey at nbompey@agu.org. Please provide your name, the name of your publication, and your phone number.

Neither the paper nor this press release is under embargo.

Title

“Winter fog is decreasing in the fruit growing region of the Central Valley of California”

Authors:
Dennis Baldocchi and Eric Waller: Department of Environmental Science, Policy and Management, University of California, Berkeley, California, USA.

Contact information for the authors:
Dennis Baldocchi: +1 (510) 642-2874, baldocchi@berkeley.edu.

AGU Contact:

Nanci Bompey
+1 (202) 777-7524
nbompey@agu.org

University of California Berkeley Contact:
Sarah Yang
+1 (510) 643-7741
scyang@berkeley.edu

Nanci Bompey | American Geophysical Union
Further information:
http://news.agu.org/press-release/californias-central-valley-sees-big-drop-in-wintertime-fog-needed-for-fruit-and-nut-crops/

Further reports about: AGU Environmental Geophysical crops nut temperature

More articles from Earth Sciences:

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

nachricht What makes erionite carcinogenic?
13.01.2017 | Friedrich-Schiller-Universität Jena

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

Im Focus: Bacterial Pac Man molecule snaps at sugar

Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.

The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...

Im Focus: Newly proposed reference datasets improve weather satellite data quality

UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration

"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...

Im Focus: Repairing defects in fiber-reinforced plastics more efficiently

Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.

Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Multiregional brain on a chip

16.01.2017 | Power and Electrical Engineering

New technology enables 5-D imaging in live animals, humans

16.01.2017 | Information Technology

Researchers develop environmentally friendly soy air filter

16.01.2017 | Power and Electrical Engineering

VideoLinks
B2B-VideoLinks
More VideoLinks >>>