Research Highlights

DEC 28

A couple very dry papers, yet pun intended

McEvoy, D.J, J.L. Huntington, J.T. Abatzoglou and L.E. Edwards, 2012, An Evaluation of Multi-scalar Drought Indices in Nevada and Eastern California, Earth Interactions, doi:

Sohrabi, M.M., J.H. Ryu, J.T. Abatzoglou and J. Tracy, 2012, Climate extremes and their linkage to regional drought over Idaho, USA, Natural Hazards, doi: 10.1007/s11069-012-0384-1


Kolden, C.A., and J.T. Abatzoglou, 2012, Climate and Vegetation Influences on Fire Impacts in Alaskan Boreal Forest: Implications for Carbon and Fire Management, Fire Ecology, doi: 10.4996/fireecology.0801098

DEC 23

I developed a methodology to create high-resolution surface meteorological conditions that include temperature, precipitation, humidity, winds and downward shortwave radiation at 4-km for the continental United States 1979-2010 by blending NLDAS-2 high-temporal resolution data with the high-spatial resolution climate dataset of PRISM.

Additional information here

Abatzoglou, J. T. (2011), Development of gridded surface meteorological data for ecological applications and modelling. International Journal of Climatology. doi: 10.1002/joc.3413

SEP 28

Multiple direct and indirect threats to invasive annual grasses expansion in western US rangelands amplified in a changing climate? This paper in Rangeland Ecology and Management provides some new insights into what might shape the west under a changing climate.

Abatzoglou JT, Kolden CA, 2011. Climate Change in Western US Deserts: Potential for Increased Wildfire and Invasive Annual Grasses. Rangeland Ecology & Management: September 2011, Vol. 64, No. 5, pp. 471-478.

JUN 28

New paper examining whether climate or weather had a bigger influence on area burned by wildfires in the Alaskan boreal forest published in International Journal of Wildland Fire.

Abatzoglou JT, Kolden CA, 2011. Relative Importance of Weather and Climate on Wildfire Growth in Interior Alaska. International Journal of Wildland Fire 20(4) 479-486.

FEB 28

Output from the novel statistical downscaling method, the Multivariate Adaptive Constructed Analogs (MACA) method, is being distributed via Inside Idaho. A companion paper has been accepted to International Journal of Climatology, "A Comparison of Downscaling methods suited for wildfire applications". A short video briefing is forthcomming on the methodology within the spectrum of other statistical downscaling methodologies.

JAN 21

Dr. Solomon Dobrowski and Shawn Crimmins led a study that I contributed to that examined the hypothesis that vegetation distributions in California moved downhill between the 1930s and 2000s in northern/central California in response to an increase in precipitation and moisture. See publication and press coverage.


Positive PNA Exacerbates Mountain Snowpack Loss in the West Large declines in mountain snowpack in the West represents an important climate impact for a variety of reasons. While prior studies have shown this loss to be consitent with climate change, and other have showed snowpack to fluctuate with the PDO, this work explicitly details how changes in the snow-level on synoptic timescales during late winter have risen over the last half century with an assist from the prevelant atmospheric mode over the West - the Pacific North American (PNA) pattern. This work shows that the shift in the PNA toward a positive phase has hastened the loss of snowpack in the West.


ENSO Climate Risks El Nino-Southern Oscillation is the single most important mode for interannual climate variability. Although most have examined ENSOs influences on climate means, this study looks at how ENSO alters the odds of climatic extremes on monthly and seasonal timescales. A set of maps illustrates the geographic and seasonal influence of active ENSO periods on the likelihood of extremely wet/dry and warm/cold periods. As ENSO is reasonably well predicted, these maps may be used for impact mitigation proactively by stakeholders in wildfire management, agriculture and land resources.


Impacts of Climate Change on Fire Danger in the West We use a new statistical downscaling method to project changes in NFDRS fire danger indices across a suite of GCMs for the late 21st century. Results suggest an increased frequency of extreme fire danger class days and an increased likelihood of synchronized extremes Westwide.

OCT 15

The MJO influence on lightning patterns across the continental US
Summertime cloud-to-ground lightning strikes are responsible for the majority of wildfire ignitions across vast sections of the seasonally dry western United States. In this study, a strong connection between active phases of the Madden Julian oscillation (MJO) and regional summertime lightning activity was found across the interior western United States. This intraseasonal mode of lightning activity emanates northward from the desert Southwest across the Great Basin and into the northern Rocky Mountains. The MJO is shown to provide favorable conditions for the northward propagation of widespread lightning activity through the amplification of the upper-level ridge over the western United States and the development of midtropospheric instability. Given the relative predictability of the MJO with long lead times, results allude to the potential for intraseasonal predictability of lightning activity and proactive fire management planning.


Characterizing Regional Climate Patterns in California
The spatial and temporal scales at which climate signals are realized are important for a variety of applications. The smaller the scale at which such information can be provided, the greater the relevance to users for most applications. However, the sparseness of high quality long-term observations is limited across much of the West. This is particularly true in regions of complex terrain where current NCDC climate divisions may be inadequate (e.g., aggregating mountain and valleys) therein necessitating an alternative characterization of regional-scale climate for user groups ranging from water managers to the energy sector. A novel approach that objectively identifies regional patterns of climate variability within the state of California using principal component analysis on monthly precipitation and temperature data from a network of 195 climate stations statewide. The confluence of large-scale circulation patterns and the complex geography of the state result in 11 regional modes of climate variability within the state. Objectively identified regions can be employed not only in tracking regional climate signatures, but also in improving the understanding of mechanisms behind regional climate variability and climate change. The analysis has been incorporated into an operational tool called the California Climate Tracker ( that provides real-time monthly updates of climate for regions across the state alongside historical data extending back to 1895.

SEP 15

How much influence does landscape-scale physiography have on air temperature in a mountain environment?
Spatio-temporal patterns of temperature in mountain environments are complex due to both regional synoptic-scale and landscape-scale physiographic controls in these systems. Understanding the nature and magnitude of these physiographic effects has practical and theoretical implications for the development of temperature datasets used in ecosystem assessment and climate change impact studies in regions of complex terrain. This study attempts to quantify the absolute and relative influence of landscape-scale physiographic factors in mediating regional temperatures and assess how these influences vary in time for a group of SNOTEL and COOP stations in the Lake Tahoe Basin in California


Fire Behavior, Weather, and Burn Severity of the 2007 Anaktuvuk River Tundra Fire, North Slope, Alaska
Abstract In 2007, the Anaktuvuk River Fire (ARF) became the largest recorded tundra fire on the North Slope of Alaska. The ARF burned for nearly three months, consuming more than 100,000 ha. The conditions potentially responsible for this large tundra fire include modeled record high summer temperature and record low summer precipitation, a late-season high-pressure system located over the Beaufort Sea, extremely dry soil conditions throughout the summer, and sustained southerly winds during the period of vegetation senescence. Burn severity mapping revealed that more than 80% of the ARF burned at moderate to extreme severity, while the nearby Kuparuk River Fire remained small and burned at predominantly (80%) low severity. While this study provides information that may aid in the prediction of future large tundra fires in northern Alaska, the fact that three other tundra fires that occurred in 2007 combined to burn less than 1000 ha suggests site specific complexities associated with tundra fires on the North Slope, which may hamper the development of tundra fire forecasting models.


California's Driest Spring in 114 years: The California Climate Tracker, a climate monitoring tool developed to characterize and track regional climate variability for the state, has shown that the spring (MAM) of 2008 was the driest in history for the state of California as a whole.  Particularly noteworthy is the dryness experienced across the central part of the state including the Central Coast, Bay Area, Sacramento-Delta and the hydrologically important Sierra Nevada, all which ranked as having the driest spring periods on record.  Two consecutive years of subpar preciptiation for the state constitues the driest period since the drought of the late 80's -early 90s, with Governor Arnold Schwarzenegger proclaiming drought for the state with water restrictions for all. Explore the California Climate Tracker