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The Influence of Soil Moisture, Coastline Curvature, and Land-Breeze Circulations on Sea-Breeze Initiated Precipitation
Idealized numerical simulations are performed with a coupled atmosphere/land-surface model to identify the roles of initial soil moisture, coastline curvature, and land breeze circulations on sea breeze initiated precipitation. Data collected on 27 July 1991 during the Convection and Precipitation Electrification Experiment (CAPE) in central Florida are used. The 3D Goddard Cumulus Ensemble (GCE) cloud resolving model is coupled with the Goddard Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model, thus providing a tool to simulate more realistically land-surface/atmosphere interaction and convective initiation. Eight simulations are conducted with either straight or curved coast-lines, initially homogeneous soil moisture or initially variable soil moisture, and initially homogeneous horizontal winds or initially variable horizontal winds (land breezes). All model simulations capture the diurnal evolution and general distribution of sea-breeze initiated precipitation over central Florida. The distribution of initial soil moisture influences the timing, intensity and location of subsequent precipitation. Soil moisture acts as a moisture source for the atmosphere, increases the connectively available potential energy, and thus preferentially focuses heavy precipitation over existing wet soil. Strong soil moisture-induced mesoscale circulations are not evident in these simulations. Coastline curvature has a major impact on the timing and location of precipitation. Earlier low-level convergence occurs inland of convex coastlines, and subsequent precipitation occurs earlier in simulations with curved coastlines. The presence of initial land breezes alone has little impact on subsequent precipitation. however, simulations with both coastline curvature and initial land breezes produce significantly larger peak rain rates due to nonlinear interactions.
Annual and sub-seasonal dynamics of a rapidly eroding permafrost coastline along the Beaufort Sea in northern Alaska
Drew Point, an unlithified ice-rich permafrost coastline along the Alaskan Beaufort Sea, is among the most rapidly eroding Arctic coastlines, with an average erosion rate of 19 m/yr from 2007 to 2019. We use 16 high-resolution remote sensing datasets (satellite, airborne, and UAV imagery) to analyze erosion mechanisms (thermal abrasion and denudation) in relation to environmental forcings along a 1.5 km stretch of coastline during the 2018 and 2019 open water seasons. In a striking contrast, 2019 exhibited the highest mean erosion rate (34.5 m) within the 2007–2019 record, while 2018 had the second lowest (11.2 m). Block failure contributed to sub-seasonal erosion rates 6 to 21 times higher than thermal denudation, with staggered block fall timing, lag responses post-storm, and non-storm block collapse influencing overall erosion magnitude and timing. To quantify wind effects, we developed wind sums, a metric combining cumulative wind speed and directional data that can be used as a proxy for integrated storm intensity capable of incorporating lagged responses that correlated strongly with erosion at sub-seasonal and annual scales. Our findings emphasize the dominant role of wind during periods of open water and air temperature during the thaw season in driving permafrost coastline erosion dynamics, while highlighting the importance of spatiotemporally high-resolution datasets for understanding Arctic coastal change dynamics.
Soil Moisture, Coastline Curvature, and Sea Breeze Initiated Precipitation Over Florida
Land surface-atmosphere interaction plays a key role in the development of summertime convection and precipitation over the Florida peninsula. Land-ocean temperature contrasts induce sea-breeze circulations along both coasts. Clouds develop along sea-breeze fronts, and significant precipitation can occur during the summer months. However, other factors such as soil moisture distribution and coastline curvature may modulate the timing, location, and intensity of sea breeze initiated precipitation. Here, we investigate the role of soil moisture and coastline curvature on Florida precipitation using the 3-D Goddard Cumulus Ensemble (GCE) cloud model coupled with the Parameterization for Land-Atmosphere-Cloud Exchange (PLACE) land surface model. This study utilizes data from the Convection and Precipitation Electrification Experiment (CaPE) collected on 27 July 1991. Our numerical simulations suggest that a realistic distribution of soil moisture influences the location and intensity of precipitation but not the timing of precipitation. In contrast, coastline curvature affects the timing and location of precipitation but has little influence on peak rainfall rates. However, both factors (soil moisture and coastline curvature) are required to fully account for observed rainfall amounts.
Geolocation Assessment Algorithm for CALIPSO Using Coastline Detection
Cloud-Aerosol Lidar Infrared Pathfinder Satellite Observations (CALIPSO) is a joint satellite mission between NASA and the French space agency CNES. The investigation will gather long-term, global cloud and aerosol optical and physical properties to improve climate models. The CALIPSO spacecraft is scheduled to launch in 2004 into a 98.2 inclination, 705 km circular orbit approximately 3 minutes behind the Aqua spacecraft. The payload consists of a two-wavelength polarization-sensitive lidar, and two passive imagers operating in the visible (0.645 mm) and infrared (8.7 - 12.0 mm) spectral regions. The imagers are nadir viewing and co-aligned with the lidar. Earth viewing measurements are geolocated to the Earth fixed coordinate system using satellite ephemeris, Earth rotation and geoid, and instrument pointing data. The coastline detection algorithm will assess the accuracy of the CALIPSO geolocation process by analyzing Wide Field Camera (WFC) visible ocean land boundaries. Processing space-time coincident MODIS and WFC scenes with the coastline algorithm will help verify the co-registration requirement with Moderate Resolution Imaging Spectrometer (MODIS) data. This paper quantifies the accuracy of the coastline geolocation assessment algorithm.
Cape Hatteras Ecological Conservation: Delineating Shoreline and Mapping Change Along the Cape Hatteras National Seashore for Coastline Management and Transportation Corridor Adaptation Strategies
The National Park Service at Cape Hatteras National Seashore works to protect North Carolina’s Outer Banks where frequent storms bring heavy winds and flooding, leading to overwash events on the main highway, North Carolina Highway 12. Shorelines are susceptible to erosion directly affecting transportation and housing infrastructures. Storm events can disrupt transportation on NC-12 and ferry service from Ocracoke Island to Hatteras Island, leaving inhabitants stranded on Ocracoke Island for indefinite amounts of time. The National Park Service’s current decision-making practices involve mitigating infrastructure damage by enlisting the help of North Carolina’s Department of Transportation and finding ways to relocate this infrastructure, as well as dredging and sediment placement that support beach nourishment efforts. Our NASA DEVELOP team partnered with the National Park Service to explore the use of optical data to delineate shoreline and map coastline change from 2014 to 2024. We used Earth observations collected by Landsat 8 Operational Land Imager, Landsat 9 Operational Land Imager-2, and Sentinel-2 MultiSpectral instrument to support decision-making related to prioritizing strategic planning for transportation corridor adaptations including potential relocation of infrastructure, and beach nourishment efforts. We derived coastline maps by consolidating images from each year to create composite images for winter and summer coastline seasonal oscillation patterns. The results highlight shoreline loss over the ~10-year study period, and the difference in shoreline inundation in the winter and summer seasons. These observations create a better understanding of successful mitigation efforts and allow the National Park Service to continue to focus on plans for infrastructure updates.
Evaluation of Clouds and the Earth's Radiant Energy System (CERES) Scanner Pointing Accuracy using a Coastline Detection System
Clouds and the Earth's Radiant Energy System (CERES) is a National Aeronautics and Space Administration (NASA) investigation to examine the role of clouds in the radiative energy flow through the Earth-atmosphere system. The first CERES scanning radiometer was launched on November 27, 1997 into a 35 inclination, 350 km altitude orbit, on the Tropical Rainfall Measuring Mission (TRMM) spacecraft. The CERES instrument consists of a three channel scanning broadband radiometer. The spectral bands measure shortwave (0.3 - 5 microns), window (8 - 12 microns), and total (0.3 - 100 microns) radiation reflected or emitted from the Earth-atmosphere system. Each Earth viewing measurement is geolocated to the Earth fixed coordinate system using satellite ephemeris, Earth rotation and geoid, and instrument pointing data. The interactive CERES coastline detection system is used to assess the accuracy of the CERES geolocation process. By analyzing radiative flux gradients at the boundaries of ocean and land masses, the accuracy of the scanner measurement locations may be derived for the CERES/TRMM instrument/satellite system. The resulting CERES measurement location errors are within 10% of the nadir footprint size. Precise pointing knowledge of the Visible and Infrared Scanner (VIRS) is required for convolution of cloud properties onto the CERES footprint; initial VIRS coastline results are included.
Multi-spectral and thermal scanner experiments along the Massachusetts coastline Final report
Aerial multispectral and infrared scanning of Massachusetts coastline
Multifrequency radiometer detection of submarine freshwater sources along the Puerto Rican coastline
The surface area above submarine springs of fresh water exhibit temperatures and salinities lower than the surrounding sea waters. A multifrequency radiometer system which earlier demonstrated an accuracy of 1 degree C and 1 part per thousand in remotely detecting the surface temperature and salinities, respectively, was used to detect submarine freshwater springs. The first mission on February 4, 1978, consisted of overflight measurements over three fourths of the coastal areas around the Island of Puerto Rico. During the second mission on February 6, 1978, special attention was directed to the northwest portion of Puerto Rico where several submarine springs had been reported. The previously reported spring locations correlated well with the locations detected by the radiometers. After separating the surface runoffs such as rivers, lagoons, marshes, and bays, 44 submarine freshwater springs were identified which indicates that the submarine freshwater outflow locations are more numerous around the island than had earlier been estimated. The majority of the submarine springs are located at the northwest and southeast portion of the Puerto Rican coastline. The success of detecting the same submarine springs during both missions at the northwest portion of the island was 39%.
Influence of meteorological conditions on aerosol vertical distribution and composition off the northeast American coastline
The size distribution and composition of lower tropospheric aerosols were measured off the northeast American coastline under clear air and disturbed meteorological conditions. Under the clear air conditions observed on 5 August 1982, with air flow from west to east, sulfate-rich stratified layers are the dominant feature of aerosol distribution in the lowest 3000 m of the troposphere. The encroachment of a warm frontal system over the study area on 9 August 1982 resulted in dramatic changes in aerosol distribution and composition prior to any precipitation, probably due to increased vertical mixing and dilution of pollutant aerosols. Chloride becomes the dominant water soluble anion in the lower 3000 m, primarily due to a several fold decrease in sulfate. Although these results are limited to only two sets of measurements, the data indicate the variability which can occur in the tropospheric vertical aerosol distributions at remote locations. A knowledge of the structure and stability of these stratified layers is of particular importance to studies of the ocean-troposphere chemistry problem.
Evaluation of ERBE scanner pointing accuracy based upon a coastline detection algorithm
Measurements from the Earth Radiation Budget Experiment (ERBE) scanning radiometers must be accurately located at the top of the Earth's atmosphere for proper interpretation of derived longwave and shortwave components of the Earth radiation field. The accuracy of the location calculations is affected by the orbit characteristics and attitude control systems of the three spacecraft, ERBS, NOAA-9, and NOAA-10. A technique was developed which makes use of the longwave scanner measurements to detect the thermal gradients at the boundaries of ocean and land masses. By analyzing many such coastline boundaries, estimates of the overall accuracy of the scanner measurement location calculations have been derived for the three satellites. The resulting measurement location errors are found to be smaller than the resolution of the radiometers, and this accuracy is well within the required location knowledge for useful science analysis of the ERBE scanner data.
Eroding Permafrost Coastlines Release Biodegradable Dissolved Organic Carbon to the Arctic Ocean
Coastal erosion mobilizes large quantities of organic matter (OM) to the Arctic Ocean where it may fuel greenhouse gas emissions and marine production. While the biodegradability of permafrost-derived dissolved organic carbon (DOC) has been extensively studied in inland soils and freshwaters, few studies have examined dissolved OM (DOM) leached from eroding coastal permafrost in seawater. To address this knowledge gap, we sampled three horizons from bluff exposures near Drew Point, Alaska: seasonally thawed active layer soils, permafrost containing Holocene terrestrial and/or lacustrine OM, and permafrost containing late-Pleistocene marine-derived OM. Samples were leached in seawater to compare DOC yields, DOM composition (chromophoric DOM, Fourier transform ion cyclotron resonance mass spectrometry), and biodegradable DOC (BDOC). Holocene terrestrial permafrost leached the most DOC compared to active layer soils and Pleistocene marine permafrost. However, DOC from Pleistocene marine permafrost was the most biodegradable (33 ± 6% over 90 days), followed by DOC from active layer soils (23 ± 5%) and Holocene terrestrial permafrost (14 ± 3%). Permafrost leachates contained relatively more aliphatic and peptide-like formulae, whereas active layer leachates contained relatively more aromatic formulae. BDOC was positively correlated with nitrogen-containing and aliphatic formulae, and negatively correlated with polyphenolic and condensed aromatic formulae. Using estimates of eroding OM, we scale our results to estimate DOC and BDOC inputs to the Alaska Beaufort Sea. While DOC inputs from coastal erosion are relatively small compared to rivers, our results suggest that erosion may be an important source of BDOC to the Beaufort Sea when river inputs are low.
Impact of U.S. west coastline inhomogeneity and synoptic forcing on winds, wind stress, and wind stress curl during upwelling season
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Using MODIS to Monitor Spatiotemporal Trends in Fog and Low Cloud Cover along the US Pacific Coastline
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Southeast Coast Ecological Conservation: Investigating the Development of Ghost Forests Due to Saltwater Intrusion along the Savannah River, Georgia Coastline of the United States
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Southeast Coast Ecological Conservation: Investigating the Development of Ghost Forests Due to Saltwater Intrusion along the Savannah River, Georgia Coastline of the United States
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Compounding of Sea‐Level Processes During High‐Tide Flooding Along the U.S. Coastline
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Changes in the Seasonal Cycle of Storm Surge Along the Global Coastline
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