Theses and Dissertations from UMD
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Item STRANDED AND SANDED IN: DRONE MOUNTED AERIAL MAGNETOMETER IDENTIFICATION OF BURIED AND SUBMERGED SHIPWRECKS ON THE NEW JERSEY COAST(2022) Davis, Cullan Matthew; Palus, Matthew; Anthropology; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)An estimated 3,000 to 7,000 shipwrecks have occurred off the coast of New Jersey, with hundreds occurring within the littoral zone. These sites have subsequently been buried by natural sand movement and beach replenishment projects or exist in a partially buried state within the surf zone. While terrestrial and vessel-mounted magnetometer surveys are not feasible in this shallow environment, the development of ultra-sensitive drone and unmanned aerial vehicle (UAV) based remote sensing platforms has provided the potential ability to rapidly identify these cultural materials for compliance and planning of weather and climate change resiliency projects. This thesis proves the capabilities of a MAGPi ML-4 atomic magnetometer, initially designed to detect small, buried munitions and unexploded ordinance of approximately eight pounds of ferrous material, to accurately and rapidly identify multiple of types of shipwrecks in the high energy coastal environment where traditional survey methods are precluded when coupled with a Matrice 600 Pro 6-rotor drone. This thesis also proved the ability for this setup to effectively bridge the gap between terrestrial and underwater archaeological surveys as presented in the littoral zone, while producing data of sufficient quality to promote the development of the theoretical understanding of the relationship between shipwrecks and the larger maritime cultural landscape. Three shipwrecks were used for data collection, representing vessels comprised of iron, wood, and steel. Additional measurements of individual ferromagnetic objects commonly found in association with shipwreck archaeological sites were taken and analyzed using predictive modeling based on magnetic detectability algorithms created from prior remote sensing surveys to determine what material can be detected using the magnetometer and UAV platform. The results of this thesis confirm the predicted capabilities of the equipment used and provides detection ranges to establish a framework to future research, including a determination on the minimum amount of wooden hull material with iron fasteners required to exist in an archaeological context to be detectable.Item Multispectral satellite remote sensing approaches for estimating cover crop performance in Maryland and Delaware(2022) THIEME, ALISON; Justice, Chris; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Winter cover crops encompass a range of species planted in late summer and fall for a variety of reasons relating to soil health, nutrient retention, soil compaction, biotic diversity, and erosion prevention. As agricultural intensification continues, the practice of winter cover cropping remains a crucial practice to reduce leaching from agricultural fields. Maryland and Delaware both incentivize cover cropping to meet water quality objectives in the Chesapeake Bay Watershed. These large-scale programs necessitate methods to evaluate cover crop performance over the landscape. Cover crop quantity and quality was measured at 2,700 locations between 2006-2021 with a focus on fields planted to four cereal species: wheat, rye, barley, and triticale. Samples were GPS located and timed with satellite remote sensing observations from SPOT 4, SPOT 5, Landsat 5, Landsat 7, Landsat 8, or Sentinel-2. When paired imagery at 10-30 m spatial resolution , there is a strong relationship between the normalized difference vegetation index (NDVI) and percent ground cover (R2=0.72) as well as NDVI and biomass (as high as R2=0.77). There is also a strong relationship between Δ Red Edge (a combination of 740 nm and 783 nm bands) and nitrogen content (R2=0.75). These equations were applied to Harmonized Landsat Sentinel-2 products and used to estimate cover crop aboveground biomass in ~300,000 ha of Maryland Department of Agricultures and ~60,000 ha of Delaware Association of Conservation Districts enrolled fields from 2019-2021 and grouped by agronomic method. Wintertime and springtime cover crop biomass varied based on planting date, planting method, species, termination date, and termination method. Early planted fields had higher wintertime biomass while fields that delayed termination had higher springtime biomass. Triticale had consistently higher biomass while wheat had the lowest biomass. Fields planted using a drill followed by light tillage or no-till drill had higher biomass, likely due to the better seed-to-soil contact. Fields that were taken to harvest or terminated for on farm use (roller crimped, green chopped) also had higher springtime biomass than other termination methods. Incentives can be used to encourage specific agronomic methods and these findings can be used to inform adaptive management in the Mid-Atlantic Region.Item A 20-YEAR CLIMATOLOGY OF GLOBAL ATMOSPHERIC METHANE FROM HYPERSPECTRAL THERMAL INFRARED SOUNDERS WITH SOME APPLICATIONS(2022) Zhou, Lihang; Warner, Juying; Atmospheric and Oceanic Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Atmospheric Methane (CH4) is the second most important greenhouse gas after carbon dioxide (CO2), and accounts for approximately 20% of the global warming produced by all well-mixed greenhouse gases. Thus, its spatiotemporal distributions and relevant long-term trends are critical to understanding the sources, sinks, and global budget of atmospheric composition, as well as the associated climate impacts. The current suite of hyperspectral thermal infrared sounders has provided continuous global methane data records since 2002, starting with the Atmospheric Infrared Sounder (AIRS) onboard the NASA EOS/Aqua satellite launched on 2 May 2002. The Cross-track Infrared Sounder (CrIS) was launched onboard the Suomi National Polar Orbiting Partnership (SNPP) on 28 October 2011 and then on NOAA-20 on 18 November 2017. The Infrared Atmospheric Sounding Interferometer (IASI) was launched onboard the EUMETSAT MetOp-A on 19 October 2006, followed by MetOp-B on 17 September 2012, then Metop-C on 7 November 2018. In this study, nearly two decades of global CH4 concentrations retrieved from the AIRS and CrIS sensors were analyzed. Results indicate that the global mid-upper tropospheric CH4 concentrations (centered around 400 hPa) increased significantly from 2003 to 2020, i.e., with an annual average of ~1754 ppbv in 2003 and ~1839 ppbv in 2020. The total increase is approximately 85 ppbv representing a +4.8% change in 18 years. More importantly, the rate of increase was derived using satellite measurements and shown to be consistent with the rate of increase previously reported only from in-situ observational measurements. It further confirmed that there was a steady increase starting in 2007 that became stronger since 2014, as also reported from the in-situ observations. In addition, comparisons of the methane retrieved from the AIRS and CrIS against in situ measurements from NOAA Global Monitoring Laboratory (GML) were conducted. One of the key findings of this comparative study is that there are phase shifts in the seasonal cycles between satellite thermal infrared measurements and ground measurements, especially in the middle to high latitudes in the northern hemisphere. Through this, an issue common in the hyperspectral thermal sensor retrievals were discovered that was unknown previously and offered potential solutions. We also conducted research on some applications of the retrieval products in monitoring the changes of CH4 over the selected regions (the Arctic and South America). Detailed analyses based on local geographic changes related to CH4 concentration increases were discussed. The results of this study concluded that while the atmospheric CH4 concentration over the Arctic region has been increasing since the early 2000s, there were no catastrophic sudden jumps during the period of 2008-2012, as indicated by the earlier studies using pre-validated retrieval products. From our study of CH4 climatology using hyperspectral infrared sounders, it has been proved that the CH4 from hyperspectral sounders provide valuable information on CH4 for the mid-upper troposphere and lower stratosphere. Future approaches are suggested that include: 1) Utilizing extended data records for CH4 monitoring using AIRS, CrIS, and other potential new generation hyperspectral infrared sensors; 2). Improving the algorithms for trace gas retrievals; and 3). Enhancing the capacity to detect CH4 changes and anomalies with radiance signals from hyperspectral infrared sounders.Item TOWARDS OBJECT-BASED EVALUATION OF INDIVIDUAL FIRES AT GLOBAL SCALES(2019) Humber, Michael Laurence; Justice, Christopher O; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Fire is a complex biophysical variable that has shaped the land surface for over 400 million years and continues to play important roles in landscape management, atmospheric emissions, and ecology. Our understanding of global fire patterns has improved dramatically in recent decades, coincident with the rise of systematic acquisition and development of global thematic products based on satellite remote sensing. Currently, there are several operational algorithms which map burned area, relying on coarse spatial resolution sensors with high temporal frequencies to identify fire-affected surfaces. While wildfires have been analyzed over large areas at the pixel level, object-based methods can provide more detailed attributes about individual fires such as fire size, severity, and spread rate. This dissertation evaluates burned area products using object-based methods to quantify errors in burn shapes and to extract individual fires from existing datasets. First, a wall-to-wall intercomparison of four publicly available burned area products highlights differences in the spatial and temporal patterns of burning identified by each product. The results of the intercomparison show that the MODIS Collection 6 MCD64A1 Burned Area product mapped the most burned area out of the four products, and all products except the Copernicus Burnt Area product showed agreement with regard to temporal burning patterns. In order to determine the fitness of the MCD64A1 product for mapping fire shapes, a framework for evaluating the shape accuracy of individual fires was developed using existing object-based metrics and a novel metric, the “edge error”. The object-based accuracy assessment demonstrated that MCD64A1 preserves the fire shape well compared to medium resolution data. Based on this result, an algorithm for extracting individual fires from MCD64A1 data was developed which improves upon existing algorithms through its use of an uncertainty-based approach rather than empirically driven approaches. The individual fires extracted by this algorithm were validated against medium resolution data in Canada and Alaska using object-based metrics, and the results indicate the algorithm provides an improvement over similar datasets. Overall, this dissertation demonstrates the capability of coarse resolution burned area products to accurately identify individual fire shapes and sizes. Recommendations for future work include improving the quality assessment of burned area products and continuing research into identifying spatiotemporal patterns in fire size distributions over large areas.Item CHARACTERIZING HYDROLOGICAL PROCESSES WITHIN THE DATA-SCARCE ENVIRONMENT OF THE CONGO BASIN(2019) Munzimi, Yolande; Hansen, Matthew C; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The Congo Basin in Africa is the world’s second largest river basin. Centrally located and with the greatest water resources in Africa, the basin is a vital resource for water and energy supply for a continent with increasing needs for safe water and energy. The Congo Basin’s streams and rivers could be impacted by human activities in the region, notably by land cover and land use change (LCLUC) considering the strong interactions between hydrology and ecosystem processes in the humid tropics. It could impact flow discharge downstream Congo River and hydropower potential at the Inga hydroelectric site, the largest such installation in Africa, located 150km upstream from the river’s mouth. The seasonal rainfall regime, to which the Congo River owes its regular flow regime, play an important role in mediating freshwater resources. An improvement to our baseline information on the Congo’s rainfall and streamflow dynamics allows for a greater quantitative understanding of the basin’s hydrology, necessary for the current and future management of Congo Basin water resources. The hydrometeorological observation network in the Congo Basin is very limited, and this environment of scarce ground data necessitates the use of remotely-sensed data for hydrological modeling. This dissertation reports the use of hydrological modeling supported by remotely-sensed data to 1) characterize precipitation and climate in the Congo Basin, 2) characterize daily streamflow across the basin, 3) assess the hydrological response to LCLUC, including the additional response caused by climatic feedbacks following LCLUC. The study uses rainfall gauge data within the Democratic Republic of Congo (DRC) to re-calibrate a TRMM science product. It then describes a physically-based parameterization of a semi-distributed hydrological model, augmented with a spatially-distributed calibration that enables the model to simulate hydrologic processes in the Congo Basin, including the slowing effect of the basin’s central wetlands, the Cuvette Centrale. Model simulations included scenarios of 25% to 100% conversion of the Basins forest cover to agricultural mosaic and compared simulated flows to those of the current baseline conditions. The dissertation also reports on the estimated impacts of the hydrological response to LCLUC on the river’s hydropower potential. Re-calibration of TRMM improved rainfall accuracy at the gauges by 15% and correctly captured important rainfall patterns such as the ones representative of the highland climate. Model calibration of daily streamflow resulted in a model with high predictive power (Nash–Sutcliffe coefficient of efficiency of 0.70) when compared to Kinshasa gauge downstream Congo River, near its outlet. Model shows realistic seasonal and spatial patterns that can be explained by the ITCZ-driven rainfall patterns in the Congo Basin. Models of the direct effects alone of 25% to 100% forest conversion produce increases in peak flows of 7% to 8%, respectively, relative to the baseline, and decreases in low flow of 1% and 6%, for 75% and 100% forest conversion respectively, relative to the baseline. However, 25% and 50% forest conversion produce increases in low flows of 3% and 1% respectively indicating a possible sensitivity of the hydrological response to the spatial variability of forest conversion. Models of the combined direct and indirect effects of 25% to 100% conversion produce decreases in peak flows of 7% to 5% respectively and decreases in low flow of 8% to 11% respectively. Model estimates of the impacts on hydropower potential range from 11% decrease during dry season to 10% increase during rainy season, with greater impacts (year-round decrease) for increasing LCLUC models including indirect effect. The modeled loss in hydropower potential during dry season reaches -5,797 MW corresponding to the hydropower potential of countries such as Zambia or Angola and of grand projects such as the Grand Ethiopian Renaissance Dam. The dissertation has showed the adequacy of TRMM precipitation products for Congo Basin rainfall regime representation and daily flow estimation particularly in capturing the timing and the seasonality of the flow. The results of these modeling efforts can be useful in research and decision-making contexts and validate the application of satellite-based hydrologic models driven for large, data-scarce river systems such as the Congo Basin by producing reliable baseline information. We recommend a prioritization of further data collection and more gauges installation required to enable further satellite-derived data calibration and models simulations. Likewise, the results from LCLUC analysis support the need for field campaigns to better understand sub-watersheds responses and to improve the calibration of currently used simulation models.Item Improving Forecasts of Volcanic Clouds: An Analysis of Observations and Emission Source Term Methods(2018) Hughes, Eric; Dickerson, Russell R; Krotkov, Nickolay A; Atmospheric and Oceanic Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Volcanic eruptions can occur with little or no warning and explosively inject dense ash and sulfur dioxide (SO2) clouds high into the atmosphere. I investigated different types of observations and analysis methods used to monitor and quantify volcanic ash and SO2 clouds. I begin with an analysis of the 2010 eruption of Eyjafjallajökull, employing ash cloud transport modeling capabilities I developed for the Goddard Earth Observing System, Version 5 (GEOS-5). The emission source terms describing the initial state of the Eyjafjallajökull ash clouds were estimated using radar observations of the ash cloud’s initial injection altitude. Results of the initial simulations agreed with operational ash forecasts from the time of the eruption and with many other published studies, but showed notable disagreement with satellite observations. The emission source term was estimated using an alternative approach, yielding simulations that better matched satellite observations. I used the result to highlight limitations of radar observations not accounted for in previous studies of the Eyjafjallajökull ash clouds. UV satellite observations are often used to monitor and quantify volcanic clouds of ash and SO2. I tested the limitations of the OMPS SO2 satellite observations using an Observing System Simulation Experiment (OSSE). The framework used GEOS-5 simulations of the atmospheric composition in the wake of a Pinatubo-like volcanic eruption to generate synthetic top-of-the-atmosphere (TOA) radiances. The TOA radiances served as input to the OMPS SO2 retrieval. In comparing the OMPS retrieval SO2 to the original GEOS-5 SO2, I found that the sulfate aerosols and ash can cause the OMPS SO2 retrieval to underestimate the total SO2 burden. These effects were amplified at increased satellite viewing angles. I finish my analysis by looking at observations from the satellite-based Cloud-Aerosol Transport System (CATS), where I show that even under the time constraints of an operational forecast, the available CATS observations were able to improve forecasts of volcanic SO2 clouds.Item TOWARDS FINE SCALE CHARACTERIZATION OF GLOBAL URBAN EXTENT, CHANGE AND STRUCTURE(2017) Wang, Panshi; Huang, Chengquan; Liang, Shunlin; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Urbanization is a global phenomenon with far-reaching environmental impacts. Monitoring, understanding, and modeling its trends and impacts require accurate, spatially detailed and updatable information on urban extent, change, and structure. In this dissertation, new methods have been developed to map urban extent, sub-pixel impervious surface change (ISC), and vertical structure at national to global scales. First, an innovative multi-level object-based texture classification approach was adopted to overcome spectral confusion between urban and nonurban land cover types. It was designed to be robust and computationally affordable. This method was applied to the 2010 Global Land Survey Landsat data archive to produce a global urban extent map. An initial assessment of this product yielded over 90% overall accuracy and good agreement with other global urban products for the European continent. Second, for sub-pixel ISC mapping, the uncertainty caused by seasonal and phenological variations is one of the greatest challenges. To solve this issue, I developed an iterative training and prediction (ITP) approach and used it to map the ISC of entire India between 2000 and 2010. At 95% confidence, the total ISC for India between 2000 and 2010 was estimated to be 2274.62±7.84 km2. Finally, using an object-based feature extraction approach and the synergy of Landsat and freely available elevation datasets, I produced 30m building height and volume maps for England, which for the first time characterized urban vertical structure at the scale of a country. Overall, the height RMSE was only ±1.61 m for average building height at 30m resolution. And the building volume RMSE was ±1142.3 m3. In summary, based on innovative data processing and information extraction methods, this dissertation seeks to fill in the knowledge gaps in urban science by advancing the fine scale characterization of global urban extent, change, and structure. The methods developed in this dissertation have great potentials for automated monitoring of global urbanization and have broad implications for assessing the environmental impact, disaster vulnerability, and long-term sustainability of urbanization.Item AGRICULTURAL LAND USE, DROUGHT IMPACTS AND VULNERABILITY: A REGIONAL CASE STUDY FOR KARAMOJA, UGANDA(2017) Nakalembe, Catherine Lilian; Justice, Christopher O; Geography; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)The increasing frequency of extreme climate events brings into question the sustainability of agriculture in marginal lands, especially those already experiencing drought such as the Karamoja region in northeastern Uganda. A significant amount of research often qualitative has been conducted documenting drought and its impact on Karamoja. Taking a mixed methods approach, this study combined remotely-sensed satellite data, national agricultural surveys, census, and field data to expand on empirical knowledge on agricultural drought, land use and human perceptions of drought necessary for comprehensive drought forecasting, monitoring, and management. Results from this study showed that Karamoja is at least twice more vulnerable to drought than any other region in Uganda. This is because of its very low adaptive capacity in part due to high poverty rates and a higher dependency on the natural environment for livelihood. Analysis of satellite data quantified a 229 percent increase in cropland area in Karamoja between 2000 and 2011/12, driven largely by agricultural development programs. Underlying forces (e.g., cropland expansion programs and controlled grazing) originating from land use policy and development programs, more than proximate causes (direct local level actions) remain the major drivers of this expansion. Although the cultivated area has dramatically increased, there is no quantifiable overall increase in yield or per-capita production as evidenced by the recurrent poor food security. This status quo, (poor yields and dependence on food aid) is likely to continue as more land is put to crop cultivation by poor households and meager investments are made in livestock-based livelihood opportunities. The cropland area mask developed in this research facilitated the characterization of drought within agricultural areas. The drought information developed by this study is spatially and temporally explicit, showing differences in severity between years and between districts. Overall Abim District showed the least variation and is the least impacted while, Moroto District had the highest inter-annual variability and was often the most severely impacted. This research presents an approach to predict the number of people who would require food aid during the lean season in Karamoja (December to March) within a reasonable margin of error (less than 10\%) at the peak of the growing season (August/September), although the need for more extensive testing is recognized. The method takes advantage of readily available satellite data and can contribute to planning for a timely and appropriate response. A case study of farmer's perceptions of drought in Moroto District found that many farmers feel helpless and have no control of their future. For the majority of farmers in the district, past experiences of drought do not necessarily impact on future expectations of drought and many have no long-term adjustment plans. Quite often the majority of the population depends on emergency food assistance, building a culture of dependency. The analysis indicates that factors such as; conflict (insecurity) and interventions by government and international agencies intermingle with culture to have a profound direct influence on farmers' perception of drought amongst communities in Moroto district. This research shows that satellite data can provide the much-needed information to fill the gaps that inhibit long-term drought monitoring, at a significantly lower cost than traditional climate station-based monitoring in data scarce regions like Karamoja. It also points to a way forward for proactive assessment, planning, and response.Item Identification and Quantification of Regional Aerosol Trends and Impact on Clouds over the North Atlantic Ocean(2017) Jongeward, Andrew; Li, Zhanqing; Atmospheric and Oceanic Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Aerosols and clouds contribute to atmospheric variability and Earth’s radiative balance across local, regional, and global scales. Originating from both natural and anthropogenic sources, aerosols can cause adverse health effects and can interact directly with solar radiation as well as indirectly through complex interactions with clouds. Aerosol optical depth (AOD) has been observed from satellite platforms for over 30 years. During this time, regional changes in emissions, arising from air quality policies and socioeconomic factors, have been suggested as causes for some observed AOD trends. In the United States, the Clean Air Act and amendments have produced improvements in air quality. In this work the impacts of improved air quality on the aerosol loading and aerosol direct and indirect effects over the North Atlantic Ocean are explored using satellite, ground, and model datasets on the monthly timescale during 2002 to 2012. It is established that two trends exist in the total AOD observed by MODIS over the North Atlantic. A decreasing AOD trend between −0.02 and −0.04 per decade is observed over the mid-latitude region. Using the GOCART aerosol model it is shown that this trend results from decreases in anthropogenic species. Ground based aerosol networks (AERONET and IMPROVE) support a decreasing trend in AOD and further strengthen links to anthropogenic aerosol species, particularly sulfate species. This anthropogenic decrease occurs primarily during spring and summer. During the same time period, MODIS also observes an increasing AOD trend of 0.02 per decade located in the sub-tropical region. This trend is shown to occur during summer and is the result of natural dust aerosol. Changes in the North African environment seen in the MERRA reanalysis suggest an accelerated warming over the Saharan Desert leads to changes in the African Easterly Jet, related Easterly Waves, and baroclinicity playing a role in an increase and northward shift in African dust. Both the direct and indirect impacts of the aerosol trends are investigated. Using the SBDART radiative transfer model, estimates of the shortwave direct radiative forcing are calculated. The decrease in anthropogenic AOD produces an increase of 2.0 ± 0.3 W/m2 per decade in the Earth-system absorbance over the mid-latitude site (37.5ºN, −68.5ºE). The increase in natural AOD results in a decrease of −1.1 ± 0.2 W/m2 per decade in the Earth-system absorbance over the sub-tropical site (23.5ºN, −55.5ºE). Evaluation of the first indirect effect demonstrates agreement with Twomey theory when considering the North Atlantic domain on the whole. A regional analysis reveals the existence of counter-Twomey behavior along the U.S. Atlantic coast. Using a daily dataset during summertime with focus on warm, non-precipitating clouds, it is found that aerosol-cloud interaction in this coastal region is sensitive to vertical velocity and aerosol size. Cases experiencing updrafts (ω < 0 Pa/s) and cases of mainly coarse-mode aerosol demonstrate good agreement with Twomey theory. Additionally, cases with low specific humidity near the cloud base show non-Twomey behavior for clouds with low liquid water path.Item IMPROVED SATELLITE MICROWAVE RETRIEVALS AND THEIR INCORPORATION INTO A SIMPLIFIED 4D-VAR VORTEX INITIALIZATION USING ADJOINT TECHNIQUES(2017) Tian, Xiaoxu; Zou, Xiaolei; Atmospheric and Oceanic Sciences; Digital Repository at the University of Maryland; University of Maryland (College Park, Md.)Microwave instruments provide unique radiance measurements for observing surface properties and vertical atmosphere profiles in almost all weather conditions except for heavy precipitation. The Advanced Microwave Scanning Radiometer 2 (AMSR2) observes radiation emitted by Earth at window channels, which helps to retrieve surface and column integrated geophysical variables. However, observations at some X- and K-band channels are susceptible to interference by television signals transmitted from geostationary satellites when AMSR2 is scanning regions including the U.S. and Europe, which is referred to as Television Frequency Interference (TFI). It is found that high reflectivity over the ocean surface is favorable for the television signals to be reflected back to space. When the angle between the Earth scene vector and the reflected signal vector is small enough, the reflected TV signals will enter AMSR2’s antenna. As a consequence, TFI will introduce erroneous information to retrieved geophysical products if not detected. This study proposes a TFI correction algorithm for observations over ocean. Microwave imagers are mostly for observing surface or column-integrated properties. In order to have vertical temperature profiles of the atmosphere, a study focusing on the Advanced Technology Microwave Sounder (ATMS) is included. A traditional AMSU-A temperature retrieval algorithm is modified to remove the scan biases in the temperature retrieval and to include only those ATMS sounding channels that are correlated with the atmospheric temperatures on the pressure level of the retrieval. The warm core structures derived for Hurricane Sandy when it moved from the tropics to the mid-latitudes are examined. Significant improvements have been obtained for the forecasts of hurricane track, but not intensity, especially during the first 6-12 hours. In this study, a simplified four-dimensional variational (4D-Var) vortex initialization model is developed to assimilate the geophysical products retrieved from the observations of both microwave imagers and microwave temperature sounders. The goal is to generate more realistic initial vortices than the bogus vortices currently incorporated in the Hurricane Weather Research and Forecasting (HWRF) model in order to improve hurricane intensity forecasts. The case included in this study is Hurricane Gaston (2016). The numerical results show that the satellite geophysical products have a desirable impact on the structure of the initialized vortex.