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Full-Text Articles in Physical Sciences and Mathematics

Simulating The Storm Environment Responsible For Nepal's First Observed Tornado, Jonathan David Douglas Meyer, Binod Pokharel, Robert R. Gillies Aug 2021

Simulating The Storm Environment Responsible For Nepal's First Observed Tornado, Jonathan David Douglas Meyer, Binod Pokharel, Robert R. Gillies

Plants, Soils, and Climate Faculty Publications

A high-resolution numerical forecast model was used to simulate the meteorological conditions leading up to the March 31st, 2019 severe weather event that produced Nepal's first-ever observed tornado. The sparse meteorologic observations in the region capturing the storm environment limit the ability to anticipate another similar situation should the particular set of conditions present themselves again. This study presents a multifaced view of the storm environment through 1) a synoptic perspective provided by the Global Data Assimilation System (GDAS) reanalysis dataset and 2) a trio of progressively higher resolution one-way nested simulations (12 km–4km–1km) driven by GDAS boundary conditions to …


Pacific Decadal Oscillation Remotely Forced By The Equatorial Pacific And The Atlantic Oceans, Zachary F. Johnson, Yoshimitsu Chikamoto, Shih-Yu Simon Wang, Michael J. Mcphaden, Takashi Mochizuki Jun 2020

Pacific Decadal Oscillation Remotely Forced By The Equatorial Pacific And The Atlantic Oceans, Zachary F. Johnson, Yoshimitsu Chikamoto, Shih-Yu Simon Wang, Michael J. Mcphaden, Takashi Mochizuki

Plants, Soils, and Climate Faculty Publications

The Pacific Decadal Oscillation (PDO), the leading mode of Pacific decadal sea surface temperature variability, arises mainly from combinations of regional air-sea interaction within the North Pacific Ocean and remote forcing, such as from the tropical Pacific and the Atlantic. Because of such a combination of mechanisms, a question remains as to how much PDO variability originates from these regions. To better understand PDO variability, the equatorial Pacific and the Atlantic impacts on the PDO are examined using several 3-dimensional partial ocean data assimilation experiments conducted with two global climate models: the CESM1.0 and MIROC3.2m. In these partial assimilation experiments, …


Projected Increase Of The East Asian Summer Monsoon (Meiyu) In Taiwan By Climate Models With Variable Performance, Yu-Shiang Tung, Shih-Yu (Simon) Wang, Jung-Lien Chu, Chi-Hua Wu, Yung-Ming Chen, Chao-Tzuen Cheng, Lee-Yaw Lin Feb 2020

Projected Increase Of The East Asian Summer Monsoon (Meiyu) In Taiwan By Climate Models With Variable Performance, Yu-Shiang Tung, Shih-Yu (Simon) Wang, Jung-Lien Chu, Chi-Hua Wu, Yung-Ming Chen, Chao-Tzuen Cheng, Lee-Yaw Lin

Plants, Soils, and Climate Faculty Publications

The active phase of the East Asian summer monsoon (EASM) in Taiwan during May and June, known as Meiyu, produces substantial precipitation for water uses in all sectors of society. Following a companion study that analysed the historical increase in the Meiyu precipitation, the present study conducted model evaluation and diagnosis based on the EASM lifecycle over Taiwan. Higher and lower skill groups were identified from 17 Couple Model Intercomparison Project Phase 5 (CMIP5) models, with five models in each group. Despite the difference in model performance, both groups projected a substantial increase in the Meiyu precipitation over Taiwan. …


Climate Diagnostics Of The Extreme Floods In Peru During Early 2017, Rackhun Son, Shih-Yu Simon Wang, Wan-Ling Tseng, Christian W. Barreto Schuler, Emily Becker, Jin-Ho Yoon Dec 2019

Climate Diagnostics Of The Extreme Floods In Peru During Early 2017, Rackhun Son, Shih-Yu Simon Wang, Wan-Ling Tseng, Christian W. Barreto Schuler, Emily Becker, Jin-Ho Yoon

Plants, Soils, and Climate Faculty Publications

From January through March 2017, a series of extreme precipitation events occurred in coastal Peru, causing severe floods with hundreds of human casualties and billions of dollars in economic losses. The extreme precipitation was a result of unusually strong recurrent patterns of atmospheric and oceanic conditions, including extremely warm coastal sea surface temperatures (SST) and weakened trade winds. These climatic features and their causal relationship with the Peruvian precipitation were examined. Diagnostic analysis and model experiments suggest that an atmospheric forcing in early 2017, which was moderately linked to the Trans-Niño Index (TNI), initiated the local SST warming along coastal …


A 100-M-Scale Modeling Study Of A Gale Event On The Lee Side Of A Long Narrow Mountain, Halie Xue, Jian Li, Tingting Qian, Hongping Gu Dec 2019

A 100-M-Scale Modeling Study Of A Gale Event On The Lee Side Of A Long Narrow Mountain, Halie Xue, Jian Li, Tingting Qian, Hongping Gu

Plants, Soils, and Climate Faculty Publications

In this study, a gale event that occurred on the lee side of a long narrow mountain was investigated, together with the associated mountain flows, using a realistic-case large-eddy simulation (LES) that is based on the Weather Research and Forecasting Model. The mountain is located on the southeastern Tibetan Plateau, where approximately 58 gales occur annually, mostly in the afternoons during the winter season. Benefitting from realistic topography and high horizontal resolution as fine as 111 m, the LES can replicate features similar to the wind fields observed during the gale period. Investigation of the early morning wind structure over …


North American Winter Dipole: Observed And Simulated Changes In Circulations, Yu-Tang Chien, Shih-Yu (Simon) Wang, Yoshimitsu Chikamoto, Steve L. Voelker, Jonathan D.D. Meyer, Jin-Ho Yoon Dec 2019

North American Winter Dipole: Observed And Simulated Changes In Circulations, Yu-Tang Chien, Shih-Yu (Simon) Wang, Yoshimitsu Chikamoto, Steve L. Voelker, Jonathan D.D. Meyer, Jin-Ho Yoon

Plants, Soils, and Climate Faculty Publications

In recent years, a pair of large-scale circulation patterns consisting of an anomalous ridge over northwestern North America and trough over northeastern North America was found to accompany extreme winter weather events such as the 2013–2015 California drought and eastern U.S. cold outbreaks. Referred to as the North American winter dipole (NAWD), previous studies have found both a marked natural variability and a warming-induced amplification trend in the NAWD. In this study, we utilized multiple global reanalysis datasets and existing climate model simulations to examine the variability of the winter planetary wave patterns over North America and to better understand …


Salt Tolerance Of Sego Supremetm Plants, Asmita Paudel, Ji Jhong Chen, Youping Sun, Yuxiang Wang, Richard M. Anderson Nov 2019

Salt Tolerance Of Sego Supremetm Plants, Asmita Paudel, Ji Jhong Chen, Youping Sun, Yuxiang Wang, Richard M. Anderson

Plants, Soils, and Climate Faculty Publications

Sego SupremeTM is a designated plant breeding and introduction program at the Utah State University Botanical Center and the Center for Water Efficient Landscaping. This plant selection program introduces native and adapted plants to the arid West for aesthetic landscaping and water conservation. The plants are evaluated for characteristics such as color, flowering, ease of propagation, market demand, disease/pest resistance, and drought tolerance. However, salt tolerance has not been considered during the evaluation processes. Four Sego SupremeTM plants [Aquilegia barnebyi (oil shale columbine), Clematis fruticosa (Mongolian gold clematis), Epilobium septentrionale (northern willowherb), and Tetraneuris acaulis var. arizonica …


Differences In Drought Tolerance Among Gisela® Cherry Rootstocks Determined Using Automated Weighing Lysimeters, Lance V. Stott, Brent Black, Bruce Bugbee Oct 2019

Differences In Drought Tolerance Among Gisela® Cherry Rootstocks Determined Using Automated Weighing Lysimeters, Lance V. Stott, Brent Black, Bruce Bugbee

Plants, Soils, and Climate Faculty Publications

The Gisela® series of dwarfing rootstock are widely used because they enable high-density production, but they may be sensitive to drought. Drought tolerance may be associated with root-zone distribution and depth or with physiological adaptation to low water potential. Here we describe a novel technique for determining physiological tolerance to drought when root distribution is held constant. In two matching studies, we continuously measured transpiration of two groups of eight trees using a 16-container automated weighing lysimeter system in a greenhouse. With this system, Gisela® 3, 5, and 12 (G.3, G.5, and G.12) rootstocks were subjected to multiple, controlled drought …


Consecutive Extreme Flooding And Heat Wave In Japan: Are They Becoming A Norm?, Shih-Yu Simon Wang, Hyungjun Kim, Dim Coumou, Jin-Ho Yoon, Lin Zhao, Robert R. Gillies Jul 2019

Consecutive Extreme Flooding And Heat Wave In Japan: Are They Becoming A Norm?, Shih-Yu Simon Wang, Hyungjun Kim, Dim Coumou, Jin-Ho Yoon, Lin Zhao, Robert R. Gillies

Plants, Soils, and Climate Faculty Publications

In July 2018, Japan experienced two contrasting, yet consecutive, extreme events: a devastating flood in early July followed by unprecedented heat waves a week later. Death tolls from these two extreme events combined exceeded 300, accompanying tremendous economic losses (BBC: July 24, 2018; AP: July 30, 2018). Meteorological analysis on these 2018 events quickly emerged (JMA-TCC, 2018; Kotsuki et al., 2019; Tsuguti et al., 2019), highlighting several compound factors: a strengthened subtropical anticyclone, a deepened synoptic trough, and Typhoon Prapiroon that collectively enhanced the Baiu rainband (the Japanese summer monsoon), fostering heavy precipitation. The comprehensive study of these events, conducted …


Climatology And Change Of Extreme Precipitation Events In Taiwan Based On Weather Types, Yi-Chao Wu, Shih-Yu (Simon) Wang, Yi-Chiang Yu, Chu-Ying Kung, An-Hsiang Wang, Sebastian A. Los, Wan-Ru Huang May 2019

Climatology And Change Of Extreme Precipitation Events In Taiwan Based On Weather Types, Yi-Chao Wu, Shih-Yu (Simon) Wang, Yi-Chiang Yu, Chu-Ying Kung, An-Hsiang Wang, Sebastian A. Los, Wan-Ru Huang

Plants, Soils, and Climate Faculty Publications

Taiwan's most significant natural hazards are caused by hydrological extremes resulting from excessive precipitation. The threat of extreme precipitation is posed by several different types of weather patterns that affect Taiwan. This study examined the bi‐decadal changes in rainfall by defining an extreme precipitation occurrence (EPO) for a range of event durations from 1 to 24 hr. Three major weather types affecting EPO in Taiwan were identified from 1993 to 2015: the front type consisting of either a frontal zone or convective systems developing with an apparent Meiyu cloudband, diurnal rainfall events when no apparent synoptic features are present, and …


Increased Variability Of Thailand's Chao Phraya River Peak Season Flow And Its Association With Enso Variability: Evidence From Tree Ring Δ18O, Chenxi Xu, Brendan M. Buckley, Parichart Promchote, S.-Y. Simon Wang, Nathsuda Pumijumnong, Wenling An, Masaki Sano, Takeshi Nakatsuka, Zhengtang Guo Apr 2019

Increased Variability Of Thailand's Chao Phraya River Peak Season Flow And Its Association With Enso Variability: Evidence From Tree Ring Δ18O, Chenxi Xu, Brendan M. Buckley, Parichart Promchote, S.-Y. Simon Wang, Nathsuda Pumijumnong, Wenling An, Masaki Sano, Takeshi Nakatsuka, Zhengtang Guo

Plants, Soils, and Climate Faculty Publications

We present a statistically robust reconstruction of Thailand's Chao Phraya River peak season streamflow (CPRPF) that spans the 202 years from 1804 to 2005 CE. Our reconstruction is based on tree ring δ18O series derived from three Pinus merkusii sites from Laos and Thailand. The regional δ18O index accounts for 57% of the observed variance of CPRPF. Spatial correlation and 21‐year running correlation analyses reveal that CPRPF is greatly influenced by regional precipitation variations associated with the El Niño–Southern Oscillation (ENSO). Periods of enhanced and reduced ENSO activity are associated with strong and weak ENSO‐streamflow correlation, …


Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai Apr 2019

Relative Salt Tolerance Of Seven Japanese Spirea Cultivars, Yuxiang Wang, Liqin Li, Youping Sun, Xin Dai

Plants, Soils, and Climate Faculty Publications

Spirea (Spiraea sp.) plants are commonly used in landscapes in Utah and the intermountain western United States. The relative salt tolerance of seven japanese spirea (Spiraea japonica) cultivars (Galen, Minspi, NCSX1, NCSX2, SMNSJMFP, Tracy, and Yan) were evaluated in a greenhouse. Plants were irrigated with a nutrient solution with an electrical conductivity (EC) of 1.2 dSmL1 (control) or saline solutions with an EC of 3.0 or 6.0 dSmL1 once per week for 8 weeks. At 8 weeks after the initiation of treatment, all japanese spirea cultivars irrigated with saline solution with an EC of 3.0 dSmL1 still exhibited good or …


Ground, Proximal, And Satellite Remote Sensing Of Soil Moisture, Ebrahim Babaeian, Morteza Sadeghi, Scott B. Jones, Carsten Montzka, Harry Vereecken, Markus Tuller Mar 2019

Ground, Proximal, And Satellite Remote Sensing Of Soil Moisture, Ebrahim Babaeian, Morteza Sadeghi, Scott B. Jones, Carsten Montzka, Harry Vereecken, Markus Tuller

Plants, Soils, and Climate Faculty Publications

Soil moisture (SM) is a key hydrologic state variable that is of significant importance for numerous Earth and environmental science applications that directly impact the global environment and human society. Potential applications include, but are not limited to, forecasting of weather and climate variability; prediction and monitoring of drought conditions; management and allocation of water resources; agricultural plant production and alleviation of famine; prevention of natural disasters such as wild fires, landslides, floods, and dust storms; or monitoring of ecosystem response to climate change. Because of the importance and wide‐ranging applicability of highly variable spatial and temporal SM information that …


Pantropical Climate Interactions, Wenju Cai, Lixin Wu, Matthieu Lengaigne, Tim Li, Shayne Mcgregor, Jong-Seong Kug, Jin-Yi Yu, Malte F. Stuecker, Agus Santoso, Xichen Li, Yoo-Geun Ham, Yoshimitsu Chikamoto, Benjamin Ng, Michael J. Mcphaden, Yan Du, Et Al. Mar 2019

Pantropical Climate Interactions, Wenju Cai, Lixin Wu, Matthieu Lengaigne, Tim Li, Shayne Mcgregor, Jong-Seong Kug, Jin-Yi Yu, Malte F. Stuecker, Agus Santoso, Xichen Li, Yoo-Geun Ham, Yoshimitsu Chikamoto, Benjamin Ng, Michael J. Mcphaden, Yan Du, Et Al.

Plants, Soils, and Climate Faculty Publications

The El Niño–Southern Oscillation (ENSO), which originates in the Pacific, is the strongest and most well-known mode of tropical climate variability. Its reach is global, and it can force climate variations of the tropical Atlantic and Indian Oceans by perturbing the global atmospheric circulation. Less appreciated is how the tropical Atlantic and Indian Oceans affect the Pacific. Especially noteworthy is the multidecadal Atlantic warming that began in the late 1990s, because recent research suggests that it has influenced Indo-Pacific climate, the character of the ENSO cycle, and the hiatus in global surface warming. Discovery of these pantropical interactions provides a …


Examination Of The Climate Factors That Reduced Wheat Yield In Northwest India During The 2000s, Avik Mukherjee, Shih-Yu (Simon) Wang, Parichart Promchote Feb 2019

Examination Of The Climate Factors That Reduced Wheat Yield In Northwest India During The 2000s, Avik Mukherjee, Shih-Yu (Simon) Wang, Parichart Promchote

Plants, Soils, and Climate Faculty Publications

In India, a significant reduction of wheat yield would cause a widespread impact on food security for 1.35 billion people. The two highest wheat producing states, Punjab and Haryana in northern India, experienced a prolonged period of anomalously low wheat yield during 2002–2010. The extent of climate variability and change in influencing this prolonged reduction in wheat yield was examined. Daily air temperature (Tmax and Tave) was used to calculate the number of days above optimum temperature and growing degree days (GDD) anomaly. Two drought indices, the standard precipitation and evapotranspiration index and the radiation-based precipitation index, …


Genetic Loci Associated With Salt Tolerance In Advanced Breeding Populations Of Tetraploid Alfalfa Using Genome-Wide Association Studies, Xiang-Ping Liu, Charles Hawkins, Michael D. Peel, Long-Xi Yu Feb 2019

Genetic Loci Associated With Salt Tolerance In Advanced Breeding Populations Of Tetraploid Alfalfa Using Genome-Wide Association Studies, Xiang-Ping Liu, Charles Hawkins, Michael D. Peel, Long-Xi Yu

Plants, Soils, and Climate Faculty Publications

Many agricultural lands in the western United States consist of soil with high concentrations of salt, which is detrimental to alfalfa (Medicago sativa L.) growth and production, especially in the region where water resource is limited. Developing alfalfa varieties with salt tolerance is imperative for sustainable production under increasing soil salinity. In the present study, we used advanced alfalfa breeding populations and evaluated five traits related to salt tolerance including biomass dry weight (DW) and fresh weight (FW), plant height (PH), leaf relative water content (RWC), and stomatal conductance (SC) under control and salt stress. Stress susceptibility index (SSI) …


Detecting Soil Macrofauna Using Ground-Penetrating Radar, Melanie N. Stock, David J. Hart, Nicholas J. Balster Jan 2019

Detecting Soil Macrofauna Using Ground-Penetrating Radar, Melanie N. Stock, David J. Hart, Nicholas J. Balster

Plants, Soils, and Climate Faculty Publications

Fossorial amphibians spend up to ten months belowground, but research into this critical habitat has been impeded by a lack of noninvasive detection methods. Ground-penetrating radar (GPR), however, offers a promising tool because amphibians have theoretically strong electromagnetic (EM) contrasts relative to the soil matrix, and thus potentially high detectability. The objectives of this study were to (1) evaluate GPR by (2) experimentally-inducing three soil thermal regimes that promote stratification in the burrowing depths of 15 Eastern American Toads (Anaxyrus americanus americanus) during the winter of 2011–2012 in Madison, WI, USA. We calculated reflectability and established the unique …


A Novel Shortwave Infrared Proximal Sensing Approach To Quantify The Water Stability Of Soil Aggregates, Azadeh Gholoubi, Hojat Emami, Scott B. Jones, Markus Tuller Oct 2018

A Novel Shortwave Infrared Proximal Sensing Approach To Quantify The Water Stability Of Soil Aggregates, Azadeh Gholoubi, Hojat Emami, Scott B. Jones, Markus Tuller

Plants, Soils, and Climate Faculty Publications

Soil structure and aggregate stability (AS) are critical soil properties affecting water infiltration, root growth, and resistance to soil and wind erosion. Changes in AS may be early indicators of soil degradation, pointing to low organic matter (OM) content, reduced biological activity, or poor nutrient cycling. Hence, efficient and reliable AS measurement techniques are essential for detection, management, and remediation of degraded soil resources. Here we quantify soil AS by developing a novel proximal sensing technique based on shortwave infrared (SWIR) reflectance measurements. The novel approach is similar to the well-documented high energy moisture characteristic (HEMC) method, which yields a …


The Influence Of Arctic Amplification On Mid-Latitude Summer Circulation, Dim Coumou, Giorgia Di Capua, Steve Vavrus, Lei Wang, Shih-Yu (Simon) Wang Aug 2018

The Influence Of Arctic Amplification On Mid-Latitude Summer Circulation, Dim Coumou, Giorgia Di Capua, Steve Vavrus, Lei Wang, Shih-Yu (Simon) Wang

Plants, Soils, and Climate Faculty Publications

Accelerated warming in the Arctic, as compared to the rest of the globe, might have profound impacts on mid-latitude weather. Most studies analyzing Arctic links to mid-latitude weather focused on winter, yet recent summers have seen strong reductions in sea-ice extent and snow cover, a weakened equator-to-pole thermal gradient and associated weakening of the mid-latitude circulation. We review the scientific evidence behind three leading hypotheses on the influence of Arctic changes on mid-latitude summer weather: Weakened storm tracks, shifted jet streams, and amplified quasi-stationary waves. We show that interactions between Arctic teleconnections and other remote and regional feedback processes could …


El Niño-Southern Oscillation Complexity, Axel Timmermann, Soon-Il An, Jong-Seong Kug, Fei-Fei Jin, Wenju Cai, Antonietta Capotondi, Kim Cobb, Matthieu Lengaigne, Michal J. Mcphaden, Malte F. Stuecker, Karl Stein, Andrew T. Wittenberg, Kyung-Sook Yun, Tobias Bayr, Han-Ching Chen, Yoshimitsu Chikamoto, Et Al. Jul 2018

El Niño-Southern Oscillation Complexity, Axel Timmermann, Soon-Il An, Jong-Seong Kug, Fei-Fei Jin, Wenju Cai, Antonietta Capotondi, Kim Cobb, Matthieu Lengaigne, Michal J. Mcphaden, Malte F. Stuecker, Karl Stein, Andrew T. Wittenberg, Kyung-Sook Yun, Tobias Bayr, Han-Ching Chen, Yoshimitsu Chikamoto, Et Al.

Plants, Soils, and Climate Faculty Publications

El Niño events are characterized by surface warming of the tropical Pacific Ocean and weakening of equatorial trade winds that occur every few years. Such conditions are accompanied by changes in atmospheric and oceanic circulation, affecting global climate, marine and terrestrial ecosystems, fisheries and human activities. The alternation of warm El Niño and cold La Niña conditions, referred to as the El Niño–Southern Oscillation (ENSO), represents the strongest year-to-year fluctuation of the global climate system. Here we provide a synopsis of our current understanding of the spatio-temporal complexity of this important climate mode and its influence on the Earth system.


Ocean Impacts On Australian Interannual To Decadal Precipitation Variability, Zachary F. Johnson, Yoshimitsu Chikamoto, Jing-Jia Luo, Takashi Mochizuki Jul 2018

Ocean Impacts On Australian Interannual To Decadal Precipitation Variability, Zachary F. Johnson, Yoshimitsu Chikamoto, Jing-Jia Luo, Takashi Mochizuki

Plants, Soils, and Climate Faculty Publications

In Australia, successful seasonal predictions of wet and dry conditions are achieved by utilizing the remote impact of sea surface temperature (SST) variability in tropical oceans, particularly the Pacific Ocean, on the seasonal timescale. Beyond seasonal timescales, however, it is still unclear which processes and oceans contribute to interannual-to-decadal wet/dry conditions in Australia. This research examines the interannual-to-decadal relationship between global SST anomalies (SSTAs) and Australian wet/dry variability by analyzing observational data and global climate model experiments conducted with the NCAR Community Earth System Model (CESM) and the Model for Interdisciplinary Research on Climate (MIROC). A 10-member ensemble simulation suite …


Regional Trends In Early-Monsoon Rainfall Over Vietnam And Ccsm4 Attribution, Rong Li, S.-Y. Simon Wang, Robert R. Gillies, Brendan Buckley, Jin-Ho Yoon, Changrae Cho Apr 2018

Regional Trends In Early-Monsoon Rainfall Over Vietnam And Ccsm4 Attribution, Rong Li, S.-Y. Simon Wang, Robert R. Gillies, Brendan Buckley, Jin-Ho Yoon, Changrae Cho

Plants, Soils, and Climate Faculty Publications

The analysis of precipitation trends for Vietnam revealed that early-monsoon precipitation has increased over the past three decades but to varying degrees over the northern, central and southern portions of the country. Upon investigation, it was found that the change in early-monsoon precipitation is associated with changes in the low-level cyclonic airflow over the South China Sea and Indochina that is embedded in the large-scale atmospheric circulation associated with a “La Niña-like” anomalous sea surface temperature pattern with warming in the western Pacific and Indian Oceans and cooling in the eastern Pacific. The Community Climate System Model version 4 (CCSM4) …


Multidecadal Variability In The Subseasonal Peak Of Low-Level Convergence Over The Pacific Warm Pool, Yen-Heng Lin, Shih-Yu (Simon) Wang Apr 2018

Multidecadal Variability In The Subseasonal Peak Of Low-Level Convergence Over The Pacific Warm Pool, Yen-Heng Lin, Shih-Yu (Simon) Wang

Plants, Soils, and Climate Faculty Publications

In the Western North Pacific (WNP), the atmospheric low-level convergence is one of the main factors that influences the genesis of tropical cyclones (TC). It has been observed that the timing of the seasonal maxima in the low-level convergence and TC genesis has shifted since the mid-1990s from mid-August to late-July, with this shift having also affected the number of TC. A multidecadal frequency of 20 years was revealed in the timing variation of the tropical intraseasonal oscillation (ISO) in the Western Pacific, in which a weak WNP low-level convergence in spring may trigger an advanced ISO phase in summer …


Accelerated Increase In The Arctic Tropospheric Warming Events Surpassing Stratospheric Warming Events During Winter, Shih-Yu (Simon) Wang, Yen-Heng Lin, Ming-Ying Lee, Jin-Ho Yoon, Jonathan D.D. Meyer, Philip J. Rasch Apr 2017

Accelerated Increase In The Arctic Tropospheric Warming Events Surpassing Stratospheric Warming Events During Winter, Shih-Yu (Simon) Wang, Yen-Heng Lin, Ming-Ying Lee, Jin-Ho Yoon, Jonathan D.D. Meyer, Philip J. Rasch

Plants, Soils, and Climate Faculty Publications

In January 2016, a robust reversal of the Arctic Oscillation (AO) took place associated with a rapid tropospheric warming in the Arctic region; this was followed by the occurrence of a classic sudden stratospheric warming in March-April. The succession of these two distinct Arctic warming events provides a stimulating opportunity to examine their characteristics in terms of similarities and differences. Historical cases of these two types of Arctic warming were identified and validated based upon tropical linkages with the Madden-Julian Oscillation and El Niño as well as those documented in previous studies. Our results indicate a recent and accelerated increase …


Empirical And Modeling Analyses Of The Circulation Influences On California Precipitation Deficits, Yen-Heng Lin, Lawrence E. Hipps, Shih-Yu (Simon) Wang, Jin-Ho Yoon Jan 2017

Empirical And Modeling Analyses Of The Circulation Influences On California Precipitation Deficits, Yen-Heng Lin, Lawrence E. Hipps, Shih-Yu (Simon) Wang, Jin-Ho Yoon

Plants, Soils, and Climate Faculty Publications

Amplified and persistent ridges in western North America are recurring features associated with drought conditions in California. The recent drought event (2012–2016) lasted through both La Niña and El Niño episodes, suggesting additional climate drivers are important in addition to the commonly perceived El Niño-Southern Oscillation. Diagnostic analyses presented here suggest that, while the Pacific North American (PNA) and North Pacific Oscillation (NPO) do not directly cause drought in California, the relationships between them and with the upper air circulation pattern do modulate the spatial drought pattern. The positive PNA relative circulation leads drier northern California, and (-NPO) relative circulation …


Development And Testing Of Cool-Season Grass Species, Varieties And Hybrids For Biomass Feedstock Production In Western North America, Steven R. Larson, Calvin H. Pearson, Kevin B. Jensen, Thomas A. Jones, Ivan W. Mott, Matthew Darwin Robbins, Jack E. Staub, Blair L. Waldron Jan 2017

Development And Testing Of Cool-Season Grass Species, Varieties And Hybrids For Biomass Feedstock Production In Western North America, Steven R. Larson, Calvin H. Pearson, Kevin B. Jensen, Thomas A. Jones, Ivan W. Mott, Matthew Darwin Robbins, Jack E. Staub, Blair L. Waldron

Plants, Soils, and Climate Faculty Publications

Breeding of native cool-season grasses has the potential to improve forage production and expand the range of bioenergy feedstocks throughout western North America. Basin wildrye (Leymus cinereus) and creeping wildrye (Leymus triticoides) rank among the tallest and most rhizomatous grasses of this region, respectively. The objectives of this study were to develop interspecific creeping wildrye (CWR) × basin wildrye (BWR) hybrids and evaluate their biomass yield relative to tetraploid ‘Trailhead’, octoploid ‘Magnar’ and interploidy-hybrid ‘Continental’ BWR cultivars in comparison with other perennial grasses across diverse single-harvest dryland range sites and a two-harvest irrigated production system. Two …


The Optical Trapezoid Model: A Novel Approach To Remote Sensing Of Soil Moisture Applied To Sentinel-2 And Landsat-8 Observations, Morteza Sadeghi, Ebrahim Babaeian, Markus Tuller, Scott B. Jones Jan 2017

The Optical Trapezoid Model: A Novel Approach To Remote Sensing Of Soil Moisture Applied To Sentinel-2 And Landsat-8 Observations, Morteza Sadeghi, Ebrahim Babaeian, Markus Tuller, Scott B. Jones

Plants, Soils, and Climate Faculty Publications

The “trapezoid” or “triangle” model constitutes the most popular approach to remote sensing (RS) of surface soil moisture based on coupled thermal (i.e., land surface temperature) and optical RS observations. The model, hereinafter referred to as Thermal-Optical TRAapezoid Model (TOTRAM), is based on interpretation of the pixel distribution within the land surface temperature - vegetation index (LST-VI) space. TOTRAM suffers from two inherent limitations. It is not applicable to satellites that do not provide thermal data (e.g., Sentinel-2) and it requires parameterization for each individual observation date. To overcome these restrictions we propose a novel OPtical TRApezoid Model (OPTRAM), which …


Gridded Snow Water Equivalent Reconstruction For Utah Using Forest Inventory And Analysis Tree-Ring Data, Daniel Barandiaran, Shih-Yu (Simon) Wang, R. Justin Derose Jan 2017

Gridded Snow Water Equivalent Reconstruction For Utah Using Forest Inventory And Analysis Tree-Ring Data, Daniel Barandiaran, Shih-Yu (Simon) Wang, R. Justin Derose

Plants, Soils, and Climate Faculty Publications

Snowpack observations in the Intermountain West are sparse and short, making them difficult for use in depicting past variability and extremes. This study presents a reconstruction of April 1 snow water equivalent (SWE) for the period of 1850–1989 using increment cores collected by the U.S. Forest Service, Interior West Forest Inventory and Analysis program (FIA). In the state of Utah, SWE was reconstructed for 38 snow course locations using a combination of standardized tree-ring indices derived from both FIA increment cores and publicly available tree-ring chronologies. These individual reconstructions were then interpolated to a 4-km grid using an objective analysis …


Sensitivity Of Seven Diverse Species To Blue And Green Light: Interactions With Photon Flux, Michael Chase Snowden, Bruce Bugbee, Kevin R. Cope Oct 2016

Sensitivity Of Seven Diverse Species To Blue And Green Light: Interactions With Photon Flux, Michael Chase Snowden, Bruce Bugbee, Kevin R. Cope

Plants, Soils, and Climate Faculty Publications

Despite decades of research, the effects of spectral quality on plant growth, and development are not well understood. Much of our current understanding comes from studies with daily integrated light levels that are less than 10% of summer sunlight thus making it difficult to characterize interactions between light quality and quantity. Several studies have reported that growth is increased under fluorescent lamps compared to mixtures of wavelengths from LEDs. Conclusions regarding the effect of green light fraction range from detrimental to beneficial. Here we report the effects of eight blue and green light fractions at two photosynthetic photon fluxes (PPF; …


Future Changes In Propagating And Non-Propagating Diurnal Rainfall Over East Asia, Wan-Ru Huang, Shih-Yu (Simon) Wang Sep 2016

Future Changes In Propagating And Non-Propagating Diurnal Rainfall Over East Asia, Wan-Ru Huang, Shih-Yu (Simon) Wang

Plants, Soils, and Climate Faculty Publications

The characteristics of diurnal rainfall in the East Asian continent consist of a propagating regime over the Yangtze River and a non-propagating regime in southeast China. Simulations of these two diurnal rainfall regimes by 18 CMIP5 models were evaluated from the historical experiment of 1981–2005. The evaluation led to the identification of one model, the CMCC-CM that replicated the key characteristics of diurnal rainfall regimes including the propagation of moisture convergence. Using the CMCC-CM to assess the future (2076–2100) change of diurnal evolution and propagation projected by the RCP4.5 experiment, it was found that propagating diurnal rainfall will enhance and …