latest news & announcements

Development of a Long-Term (1884-2006) Serially Complete Dataset of U.S. Temperatures and Precipitation for Climate Services

by: Jinsheng You, Kenneth G Hubbard, Martha Shulski

Volume 2015, No. 1, 31 Jan 2015

Serially complete climate datasets with no missing data are necessary for a diverse group of users working in many economic sectors. In this article we describe the procedures used to create a Serially Complete Data set (SCD) for the U.S. We include the selection criterion applied to potential SCD stations, the various procedural steps and the details applied to each step. A few observations that were not previously digitized were obtained from observers official paper reports. The methods used to estimate missing data are the Spatial Regression Test and the Inverse Distance Weighting technique. Using the criterion for selecting stations we were able to include 2144 stations for the SCD that had at least 1 element (maximum/minimum temperature and/or precipitation) for a continuous period of at least 40 years. In addition, the quality control procedure assigned confidence intervals to all observations and many of the estimates. We continue to explore the options for estimating any missing data that remain after our 3 step approach and we look forward to changing the base data set form TD 3200 to GHCN.

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Winter Wind Chill Climatology for the High Plains Region

by: Holly B. Lussenden, Natalie A. Umphlett, Martha D. Shulski, Daniel Ebert

Volume 2014, No. 1, 14 May 2014

During the winter months in the High Plains region of the United States, wind chill temperatures can reach dangerous levels for humans and animals. Knowing the frequency in which extreme wind chill temperatures occur could help forecasters know when to issue wind chill advisories and also the general public understand just how rare, or common, certain wind chill temperatures are. A climatology spanning a 37-year period was created using data from 57 stations in and around the plains portion of the High Plains region from the Integrated Surface Hourly Database at National Climatic Data Center (NCDC). These climatologies were completed for December, January, February, and the winter season as a whole, for the number of hours and days in which wind chills reach certain thresholds. Also included is an all-time low wind chill value by location. As one might expect, results show that some of the most extreme and more frequent low wind chill temperatures in the region occur in eastern North Dakota and northwestern Minnesota. In this area, several days per year can reach -40°F or lower, a temperature at which frostbite can occur within minutes. The highest number of wind chills less than or equal to -10°F occurred in January, with December and February having similar distributions of wind chill occurrence.

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by: Adnan Akyüz, Karsten Shein, Mike Asmus

Volume 2013, No.1, 31 May 2013

Trace is the amount of precipitation that is less than 0.005” (AMS, 1959). Generally, it is not a measurable amount but just enough to wet the rain gauge that it is observed in. It is a global practice that “T” (indicating “Trace”) is entered in daily precipitation records such as the National Weather Service form B-91 under the precipitation column. Although trace is not a quantitative value, it is valuable information to better assess the weather condition of the day. However, when the precipitation data are tabulated, most spreadsheet programs do not know how to deal with a character that is not a numerical value. We explain a procedure for including trace observations when evaluating precipitation behavior over a period of time or between multiple time periods. This procedure temporarily assigns a computationally insignificant value to trace observations in order to incorporate those observations into database calculations (e.g. number of precipitation days) as well as also greatly reduce the chance of ties in the precipitation rankings. Our procedure allowed us to separate individual precipitation events in perspective especially in ranking tables without changing accumulated monthly, seasonal or annual precipitation values, thus preserving the climate history of the location.

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Extension Agent Awareness of Climate and New Directions for Research in North Carolina

by: Norman Breuer, Heather Dinon, Ryan Boyles, Gail Wilkerson

Volume 2012, No. 2, 6 Mar 2012

Each state in the United States of America has an institution known as the Cooperative Extension Service. These institutions, almost always associated with the Land Grant University’s tripartite mission of research, education, and extension, are in essence providers of adult education. In the case of climate science, they have been called a boundary organization which serves as a two-way intermediary between climate researchers and end-users. In order to better collaborate with the Extension Service, this investigation explored their attitudes toward, knowledge of, and willingness to use climate information and seasonal climate forecasts. A survey instrument was developed and distributed to North Carolina extension personnel in March 2009. A total of 109 responses were retrieved and analyzed. A principal finding is that extension agents need and desire to gain a better understanding of climate science and its application to agricultural practices. The respondents find seasonal climate forecasts to be useful and understand the economic value of forecast guidance. However, requested accuracy of seasonal climate forecasts is beyond the skill of current climate models. The survey results are discussed as well as their implication for future work in climate assessment programs regarding information to reduce risk in agriculture and natural resource management. In general, extension will continue to be a valued partner for the dissemination of climate tools and products by serving as an intermediary between climate scientists and end-users. This feedback loop can tailor and improve formats, content, presentation, access, and credibility of climate risk reduction decision support systems.

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by: Robert J. Leffler

Volume 2012, No. 1, 6 Mar 2012

The winter of 2009-2010 in the Washington D.C. area will likely be remembered by many arearesidents as the snowiest in their lifetimes. A rare combination of a weak-to-moderate El Nino (wet) anda very persistent negative North Atlantic Oscillation (NAO) (cold) brought a potent combination of sub-tropical moisture and cold air together over the mid-Atlantic states including the nation’s capital, resulting in an unprecedented number of major snowstorms and totalsnowfall. The extreme winter snowfalls during the most intense periods of the winter earned the winter the nickname “Snowmageddon”.

The largest snowfallsoccurred to the north of the Capital and west and northwest of Baltimore in north-central Maryland. An analysis of historical snowfall reports for the Washington D.C. metropolitan area suggests Snowmageddon’s snowfalls were unprecedented in number and amount since historical reports are available beginning in early colonial times in the early 1600’s.


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by: Morgan Phillips, Nolan Doesken

Volume 2011, No. 2, 21 Jun 2011

The winter and early spring of 2008-2009 brought an unusually high number of alpine dust deposition events to the Rocky Mountains of Colorado. The greatest dust accumulations were observed in the San Juan Mountains of southwestern Colorado. Significant dust accumulation was even observed along the Continental Divide in northern Colorado. The primary source for this dust has previously been identified as the Colorado Plateau. Analysis using the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) atmospheric trajectory model along with satellite imagery showed that dust from the 2009 events also originated from the Colorado Plateau, especially from areas in and around northeastern Arizona that were experiencing abnormally dry conditions that spring.

The study utilized data from the BLM/USFS Remote Automated Weather Station (RAWS) network in the southwestern U.S. to identify periods of high winds corresponding to documented Colorado dust events.The RAWS database, once considered to be brief and unsuitable as a climate resource, is quickly approaching 30 years of record and provides a valuable resource for application to various climate questions. Analysis of wind data from these RAWS sites during known dust events show that a minimum threshold wind velocity exists before dust storm generation occurs, and that this threshold velocity occurs from a southwesterly direction. Threshold velocity for the daily mean speed was found to be 15 mph and 44 mph for daily maximum gusts. Wind speeds for the study region were then evaluated for the period January through April for the past 20 years in an attempt to quantify and compare both mean daily wind speed and maximum daily wind gusts on a seasonal basis. A linear regression analysis showed correlation between the Southern Oscillation Index (SOI) and the frequency of these types of high wind periods in the RAWS database, particularly during winter months. This correlation was determined to be 0.46 for daily mean wind speeds and 0.56 for maximum daily wind gusts during the months of December through April. The correlation between periods of high winds and the SOI extends through the 20 years of wind data available for these weather stations.

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by: Theodore W. Sammis, Junming Wang, David R. Miller

Volume 2011, No. 1, 21 Feb 2011

This paper reviews the history of calculating “consumptive water use,” later termed evapotranspiration (Et), for plants in the western U.S. The Blaney-Criddle formula for monthly and seasonal consumptive water use was first developed for New Mexico in 1942 for limited crops. The formula was based on the input of monthly mean air temperature and an empirical monthly/seasonal coefficient. Subsequent changes improved the Blaney-Criddle formula by adding more weather and crop variables. The availability of data from automated weather stations, after about 1980, that measure more weather input variables has allowed the empirical Blaney-Criddle formula to be replaced by the mechanistic standardized Penman-Monteith equation with an appropriate crop coefficient to calculate Et. The Penman-Monteith equation calculates Et under non-stressed conditions and represents the maximum Et and associated yield of the crop.

Water rights in the western U.S. have historically, and continue to be, adjudicated using variations of the Blaney-Criddle formula. The Blaney-Criddle formula, derived in farmers’ fields under water stress conditions, calculates an Et that is most closely related to average county yields during the years the measurements were taken. But the empirical relationship and the originally derived coefficients are outdated and invalid for today’s agriculture production systems and should be replaced with the Penman-Monteith equation when adjudicating water rights.

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by: Norman E. Breuer, Clyde W. Fraisse, Peter E. Hildebrand

Volume 2009, No. 5, 7 October 2009

We used a participatory approach for research, development, and dissemination of AgroClimate, a decision support system for climate risk reduction in agriculture. Feedback from stakeholders and dissemination of climate forecast technology were simultaneous outputs from interactions with potential end users. We describe the research and development process, including the use of Sondeos (a semi-structured, multidisciplinary team discussion process), focus groups, semi-structured interviews, web-surveys, on-line feedback and participation at farmer association meetings. Quality and quantity of feedback, cost, number of activities, and numbers of stakeholders reached were scaled for analysis. Radar diagrams were used to characterize the several research participatory methodologies used. Results showed that all methods were useful. The greatest quantity of feedback was obtained through Sondeos, interviews, and a web survey. The greatest quality of feedback came from the web survey, workshops, interviews and Sondeos. Dissemination of climate forecast technology and applications available on AgroClimate were greatest at farmer association meetings and lowest at workshops. All methods mentioned are appropriate loci for two-way translational science to occur. While disseminating climate information, feedback and new ideas from potential end users are obtained. Thus AgroClimate and many of the tools within it may be thought of as having been co-developed by scientists and stakeholders.


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Alan R. Bender 1944-2008

by: Dennis Todey

Volume 2009, No. 4, 4 June 2009

Alan R. Bender, 63, of Volga, S.D., died suddenly in Brookings on Wednesday, Aug. 27, 2008. In 1979 he became an engineer and assistant professor of agricultural engineering at SDSU and the following year he completed his master’s degree in agricultural engineering. In 1984 he was named acting director of the SDSU Water Resource Institute, a position he held until 1991. The previous year, he had been named an assistant professor and agricultural engineer in Extension and acting water quality coordinator. From 1991 to 2001 he was South Dakota’s state climatologist. His contributed significantly to the disciplinary knowledge base and helped pioneer many new processes through each of these positions; his professional achievements are too numerous to

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Integrating the Natural Climate Regime into Management Plans for Swine Wastewater Lagoons

by: Charles L. Wax, Jonathan W. Pote, Michael E. Brown

Volume 2009, No. 3, 1 Jun 2009

Disposal of wastewater from large-scale swine production facilities in the southern region of the U.S. is increasingly problematic as production facilities increase and regulations governing disposal become more restrictive. No-discharge systems are attractive or even mandatory for many producers. In such systems, wastewater is pumped from a storage lagoon when a certain level of storage is reached, and proper disposal depends on evaporation, infiltration into the soil,  and on a crop's ability to utilize some nutrient such  as nitrogen or phosphorus at that time. Under the control of climate in the region, lagoon levels rise during periods of precipitation while the soil becomes wet and the net water requirement of plants decreases, precluding irrigation.  Wastewater volume is therefore typically high du ring winter and spring when pumping would be ecologically damaging, and low during summer and fall when conditions are more often suitable for successful land application. Consequently, at the moment of greatest need this type of disposal system is not operational, and spills or illegal discharges may occur. This study uses daily computer simulation over a 45-year period to test how well five management strategies could remedy this offset distribution of wastewater supply and demand.  Pumping once each year on planned dates of the 15th of June, July, August, and September do successfully shift the time of necessary pumping out of the winter and spring and into the growing season. An annual September 15 th pumping of lagoons is recommended as the most efficient management plan for avoiding illegal overflows and emergency pumping at times when land application will not be successful.   

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