429 research outputs found

    Quantitative Assessment of Drought Impacts Using XGBoost based on the Drought Impact Reporter

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    Under climate change, the increasing frequency, intensity, and spatial extent of drought events lead to higher socio-economic costs. However, the relationships between the hydro-meteorological indicators and drought impacts are not identified well yet because of the complexity and data scarcity. In this paper, we proposed a framework based on the extreme gradient model (XGBoost) for Texas to predict multi-category drought impacts and connected a typical drought indicator, Standardized Precipitation Index (SPI), to the text-based impacts from the Drought Impact Reporter (DIR). The preliminary results of this study showed an outstanding performance of the well-trained models to assess drought impacts on agriculture, fire, society & public health, plants & wildlife, as well as relief, response & restrictions in Texas. It also provided a possibility to appraise drought impacts using hydro-meteorological indicators with the proposed framework in the United States, which could help drought risk management by giving additional information and improving the updating frequency of drought impacts. Our interpretation results using the Shapley additive explanation (SHAP) interpretability technique revealed that the rules guiding the predictions of XGBoost comply with domain expertise knowledge around the role that SPI indicators play around drought impacts.Comment: 4 pages with 2 figures and 1 table. NeurIPS workshop on Tackling Climate Change with Machine Learning, 202

    Estimation of Daily Air Temperature Based on MODIS Land Surface Temperature Products over the Corn Belt in the US

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    Air temperature (Ta) is a key input in a wide range of agroclimatic applications. Moderate Resolution Imaging Spectroradiometer (MODIS) Ts (Land Surface Temperature (LST)) products are widely used to estimate daily Ta. However, only daytime LST (Ts-day) or nighttime LST (Ts-night) data have been used to estimate Tmax/Tmin (daily maximum or minimum air temperature), respectively. The relationship between Tmax and Ts-night, and the one between Tmin and Ts-day has not been studied. In this study, both the ability of Ts-night data to estimate Tmax and the ability of Ts-day data to estimate Tmin were tested and studied in the Corn Belt during the growing season (May–September) from 2008 to 2012, using MODIS daily LST products from both Terra and Aqua. The results show that using Ts-night for estimating Tmax could result in a higher accuracy than using Ts-day for a similar estimate. Combining Ts-day and Ts-night, the estimation of Tmax was improved by 0.19–1.85, 0.37–1.12 and 0.26–0.93 °C for crops, deciduous forest and developed areas, respectively, when compared with using only Ts-day or Ts-night data. The main factors influencing the Ta estimation errors spatially and temporally were analyzed and discussed, such as satellite overpassing time, air masses, irrigation, etc

    Selecting maize for rapid kernel drydown: timing of moisture measurement

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    Previous studies have shown that maize ear moisture measured using a modified Electrophics Moisture Meter model MT808 was highly correlated to kernel moisture and could be used as a selection tool in breeding maize genotypes with faster rates of kernel drydown. Such a tool would need to be standardized for practical and routine use in a breeding program with large numbers of plants. The objective of this study was to determine the opti¬mum time for measuring ear moisture using this meter. In a split-plot design with three replicates in 2007, 2008 and 2009, ear moisture of six inbred lines and eight F1 hybrids were measured weekly from one to eight weeks post-silking using a modified MT808 moisture meter. To determine if multiple ear moisture readings (EMRs) could be made on the same ear, an additional treatment was added so that all eight readings were made on the same ear. There was a positive correlation between weekly EMRs readings done on separate ears and those done on the same ear, indicating that repeated readings, if desired, could be made on the same ear. Significant genotypic differences in EMRs were found five to eight weeks post-silking. The EMRs at week one, five, and eight could be used to calculate a daily drydown rate (DDR). Maize genotypes (hybrids and inbreds) could be divided into four groups based on their DDRs during development as: high-high, high-low, low-high, and low-low DDRs from weeks one to five and five to eight, respectively. Genotypes with higher DDRs from weeks one to five tended to have overall higher DDRs by eight weeks post-silking. Inbred lines with higher DDRs at either stage expressed this trait in their hybrid crosses. This non-destructive method will improve selection for fast kernel drydown in maize breed¬ing programs, especially in short-season areas

    Assessing the Vegetation Condition Impacts of the 2011 Drought across the U.S. Southern Great Plains Using the Vegetation Drought Response Index (VegDRI)

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    The vegetation drought response index (VegDRI), which combines traditional climate- and satellite-based approaches for assessing vegetation conditions, offers new insights into assessing the impacts of drought from local to regional scales. In 2011, the U.S. southern Great Plains, which includes Texas, Oklahoma, and New Mexico, was plagued by moderate to extreme drought that was intensified by an extended period of recordbreaking heat. The 2011 drought presented an ideal case study to evaluate the performance of VegDRI in characterizing developing drought conditions. Assessment of the spatiotemporal drought patterns represented in the VegDRI maps showed that the severity and patterns of the drought across the region corresponded well to the record warm temperatures and much-below-normal precipitation reported by the National Climatic Data Center and the sectoral drought impacts documented by the Drought Impact Reporter (DIR). VegDRI values and maps also showed the evolution of the drought signal before the Las Conchas Fire (the largest fire in New Mexico’s history). Reports in the DIR indicated that the 2011 drought had major adverse impacts on most rangeland and pastures in Texas and Oklahoma, resulting in total direct losses of more than $12 billion associated with crop, livestock, and timber production. These severe impacts on vegetation were depicted by the VegDRI at subcounty, state, and regional levels. This study indicates that the VegDRI maps can be used with traditional drought indicators and other in situ measures to help producers and government officials with various management decisions, such as justifying disaster assistance, assessing fire risk, and identifying locations to move livestock for grazing

    Urinary Aflatoxin M1 Concentration and Its Determinants in School-Age Children in Southern Ethiopia

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    Aflatoxins are mycotoxins that can contaminate grains, legumes, and oil seeds. These toxic compounds are an especially serious problem in tropical and sub-tropical climates. The objective of this study was to raise awareness of aflatoxin exposure among primary school children in Shebedino woreda, southern Ethiopia, by measuring urinary aflatoxin M1 (AFM1). The study employed a cross-sectional design and systematic random sampling of children from eight schools in the district. The mean ± SD age of the children was 9.0 ± 1.8 years. Most (84.6%) households were food insecure with 17.9% severely food insecure. Urinary AFM1 was detected in more than 93% of the children. The median [IQR] concentration of AFM1/Creat was 480 [203, 1085] pg/mg. Based on a multiple regression analysis: DDS, consumption of haricot bean or milk, source of drinking water, maternal education, and household food insecurity access scale scores were significantly associated with urinary AFM1/Creat. In conclusion, a high prevalence of urinary AFM1 was observed in this study. However, the relation between AFM1 and dietary intake was analyzed based on self-reported dietary data; hence, all of the staple foods as well as animal feeds in the study area should be assessed for aflatoxin contamination

    Polarization quantum properties in type-II Optical Parametric Oscillator below threshold

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    We study the far field spatial distribution of the quantum fluctuations in the transverse profile of the output light beam generated by a type II Optical Parametric Oscillator below threshold, including the effects of transverse walk-off. We study how quadrature field correlations depend on the polarization. We find spatial EPR entanglement in quadrature-polarization components: For the far field points not affected by walk-off there is almost complete noise suppression in the proper quadratures difference of any orthogonal polarization components. We show the entanglement of the state of symmetric intense, or macroscopic, spatial light modes. We also investigate nonclassical polarization properties in terms of the Stokes operators. We find perfect correlations in all Stokes parameters measured in opposite far field points in the direction orthogonal to the walk-off, while locally the field is unpolarized and we find no polarization squeezing.Comment: 16 pages, 18 figure

    Entanglement Creation Using Quantum Interrogation

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    We present some applications of high efficiency quantum interrogation ("interaction free measurement") for the creation of entangled states of separate atoms and of separate photons. The quantum interrogation of a quantum object in a superposition of object-in and object-out leaves the object and probe in an entangled state. The probe can then be further entangled with other objects in subsequent quantum interrogations. By then projecting out those cases were the probe is left in a particular final state, the quantum objects can themselves be left in various entangled states. In this way we show how to generate two-, three-, and higher qubit entanglement between atoms and between photons. The effect of finite efficiency for the quantum interrogation is delineated for the various schemes.Comment: 7 pages, 13 figures, Submitted to PR
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