bibliography1.html

Bibliography for the Regional Assessment of Climate Variability and Impact of Climate Forecasts on the Americas.
FOCUS: Florida and the S.E. U.S.A.

Impact of ENSO-Related Climate Anomalies on Crop Yields in the US [Abstract] / [HTML] / [PDF]
David M. Legler, Kelly J. Bryant, and James J. O'Brien
Submitted to Climatic Change, April 1998

El Niño-Southern Oscillation Impacts on Winter Vegetable Production in Florida [PDF] / [Abstract]
James W. Hansen, James W. Jones, Clyde F. Kiker and Alan W. Hodges
Accepted to Journal of Climate

El Niño - Southern Oscillation Influences on Florida Crop Yields [PDF] / [Abstract]
James W. Hansen, Ayse Irmak, and James W. Jones
Submitted to Soil and Crop Science Society of Florida Proceedings

ENSO Influences on Agriculture in the Southeastern US [PDF] / [Abstract]
James W. Hansen, Alan W. Hodges, and James W. Jones
Journal of Climate 11(3):404-411. (c) 1998 American Meteorological Society

Impact of ENSO-Related Climate Anomalies on Crop Yields in the US [HTML] / [PDF]

David M. Legler, Kelly J. Bryant, and James J. O'Brien
Submitted to Climatic Change, April 1998

Historical daily thermal and precipitation data from selected stations across the United States are composited into climate scenarios for the three phases of ENSO: Warm Events (El Niño), Cold Events (El Viejo or La Niña), and Neutral. Using these scenarios, yields of 7 field crops were simulated using the EPIC biophysical model during the one-year period coincident with maximum SST anomalies in the equatorial Pacific. The response of simulated agricultural productivity to the ENSO-related climate-variability parameters, is presented.

A sensitivity calculation confirms the relevance of precipitation totals/medians and suggests ENSO-related yields are sensitive to changes in statistical properties characterizing precipitation distribution and occurrence. Results are spatially dependent, with the southwest and northern plains regions indicating the highest sensitivity to the inclusion of additional precipitation characteristics. The southeast yields are not as sensitive.

The yield deviations (expressed as normalized differences to neutral yields) associated with the two extreme ENSO phases (Warm Events and Cold Events) are spatially and crop dependent with ranges up to 120%. The largest yield deviations are in the south, southwest, and northern plains. Overall, Cold Events demonstrate larger impacts in the southern regions and Warm Events have a larger impact in the north. Additionally, the notion that climate anomalies associated with Cold and Warm Events and subsequent impacts on yields should be of opposite sign (ie, linear) is not valid in many regions. For the eastern half of the US, modeled yield deviations under Warm Event conditions are nearly all less than neutral. Conversely, in the western half, results are more mixed. Under Cold Event conditions, yields in the east are enhanced in the south, but worsened in the north; while in the western half, yields have decreased in general.

The results highlight the critical role of climate and production-related data on station or county levels in quantifying the impact of ENSO climate anomalies on yields. Both the diverse nature of the ENSO-related yield deviations as well as their sensitivity to monthly frequency distribution and occurrence characteristics imply that ENSO-related seasonal precipitation forecasts might be beneficial for agricultural application only if details were provided regarding not only totals, but also predicted changes in temporal and spatial variability of a more comprehensive suite of characteristics.

El Niño-Southern Oscillation Impacts on Winter Vegetable Production in Florida [PDF]
James W. Hansen, James W. Jones, Clyde F. Kiker and Alan W. Hodges
Accepted to Journal of Climate

Abstract:
Florida's mild winters allow the state to play a vital role in supplying fresh vegetables for US consumers, and producers to benefit from premium prices when low temperatures prevent production in most of the country. This study characterizes the influence of the El Niño-Southern Oscillation (ENSO) on the Florida vegetable industry using statistical analysis of the response of historical crop (yield, prices, production and value) and weather variables (freeze hazard, temperatures, rainfall and solar radiation) to ENSO phase and its interaction with location and time-of-year. Rainfall was higher, and daily maximum temperatures and solar radiation were lower in El Niño than in neutral or La Niña winters (Fig 1). ENSO phase had no apparent influence on indices of freeze hazard. Annual mean yields showed little evidence of response to ENSO phase and its interaction with location. ENSO phase and season interacted to influence quarterly yields, prices, production and value. Yields (tomato, bell pepper, sweet corn and snap bean) were lower (Fig. 2) and prices (bell pepper and snap bean) were higher (Fig. 3) in El Niño than in neutral or La Niña winters, but were generally unaffected by ENSO phase in fall and spring quarters. Production and value of tomato were higher in La Niña winters. The mean yield decrease in El Niño years exceeded 23% of the long-term average for tomato and bell pepper (Table 1). The yield response can be explained by increased rainfall, and reduced daily maximum temperatures and solar radiation in El Niño winters. Prices averaged $464 Mg or 30.6% higher -1 for bell pepper and $313 Mg or 21.0% higher for snap bean in El Niño than in neutral or La Niña -1 winters. Yield and production of winter vegetables appeared to be less responsive to ENSO phase after 1980; for tomato and bell pepper, this may be due to improvements in production technology that mitigate problems associated with excess rainfall. Winter yield and price responses to El Niño events have important implications for both producers and consumers of winter vegetables, and suggest opportunities for further research.

El Niño - Southern Oscillation Influences on Florida Crop Yields [PDF]
James W. Hansen, Ayse Irmak, and James W. Jones
Submitted to Soil and Crop Science Society of Florida Proceedings

Abstract:
Submitted for publication in Soil and Crop Science Society of Florida Proceedings Ð Volume 57 Summary: The El Niño-Southern Oscillation (ENSO) can influence crop production through its interactions with weather. To identify cropping enterprises in Florida that are vulnerable to ENSO-related weather variability, we analyzed the influence of ENSO phases on historical yields of annual field crops (maize, soybean, peanut), sugarcane, vegetables (potatoes, eggplant, strawberry, celery, pepper, tomatoes, snap bean and sweet corn) and citrus (oranges, limes, grapefruit, temples, tangelos and tangerines) (Tables 1 and 2). Sugarcane yield anomalies about a smoothed trend were higher following La Niña than following neutral or El Niño years. Annual mean yield anomalies of bell pepper, and winter yield anomalies of tomato, bell pepper, snap bean and sweet corn were lower in El Niño than in neutral or La Niña years. Yield anomalies were higher for grapefruit and tangerine, and lower for lime in years following El Niño than in years following neutral or La Niña events. Thus, although ENSO-related weather variability explained a significant portion of yield variability of a broad range of Florida crops, the direction, magnitude and timing of the effect depended on the particular crop. These results suggest a potential for farmers to modify practices for expected weather conditions based on knowledge of the ENSO phase.

ENSO Influences on Agriculture in the Southeastern US [PDF]
James W. Hansen, Alan W. Hodges, and James W. Jones
Journal of Climate 11(3):404-411. (c) 1998 American Meteorological Society

Abstract:
Summary: The influence of El Niño-Southern Oscillation (ENSO) on crop production in the southeastern US was studied to identify crops that are vulnerable to ENSO-related weather variability and therefore likely to benefit from application of ENSO-based climate forecasts. We analyzed the historical (1960-1995) response of total value and its components (yield, area harvested and price) to ENSO phases and quarterly sea surface temperature anomalies (SST) in the eastern equatorial Pacific for six crops (peanut, tomato, cotton, tobacco, corn and soybean) in four states (Alabama, Florida, Georgia and South Carolina). To account for the influence of changing technology and other sources of long-term variability, we evaluated and applied a harmonic smoothing technique to separate low-frequency trends from higher-frequency response to weather variability for each data series (Fig. 1). Analyses were performed on anomalies (observed minus smoothed) from the trend. Response to current and previous ENSO phases was analyzed by analysis of variance (ANOVA). ENSO phase significantly influenced corn and tobacco yields, the areas of soybean and cotton harvested, and the values of corn, soybean, peanut and tobacco (Table 1). ENSO phases explained an average shift of $212 million, or 25.9%, of the value of corn (Table 2). Shifts in May and June rainfall explain the maize yield response to ENSO phase. We used canonical correlation analysis (CCA) to analyze relationships between crop data series (yields, prices, harvested areas and values) and a set of quarterly SST series at different lags relative to the cropping season. CCA identified significant responses of corn, soybean and cotton yields, and peanut value to SST across the region; and of peanut and tobacco yields, and tomato and soybean values in particular states.

The North American Climate Patterns Associated With The El Niño Southern Oscillation [PDF] / [Abstract] / [HTML]
P. M. Green, D. M. Legler, C. J. Miranda V, and J. J. O'Brien
COAPS Project Report Series 97-1, March 1997

In this short report, we present artistic renditions of the changes in precipitation and temperature for each of the four seasons surrounding the mature phase of a warm (El Niño) or a cold (El Viejo) ENSO event. Over 60 million individual climate observations were used to construct this climatology of ENSO impacts over North America.

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Last updated on April 13, 1998