During the mid-Holocene (MH, 6,000 years BP), precessional forcing drove enhanced monsoon rainfall, expanded vegetation cover, and reduced dust emissions throughout the African Sahara. The orbital forcing and feedback of vegetation albedo have been widely studied with climate models, but are found to be insufficient to explain the magnitude and location of rainfall anomalies suggested from proxy reconstructions. The feedback of reduced Saharan dust loading has been less-studied because Paleoclimate Modelling Intercomparison Project (PMIP) Phase 2/3 models did not incorporate the decreased MH Saharan dust emissions. Several recent modeling studies investigated the MH Saharan hydroclimate response to reduced dust loading; however, their models only resolved the direct effect from dust aerosols (i.e. direct radiative forcing), which leaves the contribution from indirect dust aerosol effects (i.e. dust aerosol-cloud interactions) largely unknown. Here we investigate the hydroclimate response due to Saharan dust using CESM CAM5-chem, which includes both the direct and indirect dust aerosol effects. In the simulations, reduced Saharan dust directly increases monsoon season (JJAS) net shortwave radiative flux at the surface, which drives continental warming. Convective clouds and convective precipitation are subsequently enhanced and, due to the overwhelming convective nature of this monsoonal region, total Saharan (20–31°N, 20°W–30°E) precipitation increases by 11.9%. However, indirect dust aerosol effects counteract the increase from convection precipitation. A reduction in Saharan dust decreases cloud nuclei number concentration and increases cloud droplet size, which in turn reduces stratus cloud cover and large-scale stable rainfall. Overall, the decrease in large-scale stable rainfall due to indirect dust effects reduces total precipitation by 12.5%. The total rainfall increase of 0.27 mm/day from reduced dust is significant but smaller than the response to changes in vegetation cover (1.19 mm/day). While these results indicate that less Saharan dust during the MH likely enhanced Saharan rainfall, they also suggest that a reduction in the indirect effects of dust likely dampened the overall response of rainfall to the MH dust forcing.

Tomographic analysis of Pn arrivals times—the guided P-wave propagating within the lithospheric mantle—is ideal for studying the structure of the uppermost mantle. While plate-scale seismic images of Pn wave speeds are common beneath the continents, similar scale studies have not been possible within ocean basins due to the sparsity of seismic stations. The Cascadia Initiative (CI) dataset provides the first opportunity to image spatial variations in lithospheric structure across an entire oceanic plate. We measure 2,862 Pn arrivals from local earthquakes recorded by the CI array. Our dataset provides complete coverage of both the Juan de Fuca (JdF) and deforming Gorda plates. We invert the measured arrival times for 3D variations in anisotropic P-wave velocity and hypocentral parameters. Despite surficial evidence of extensive active faulting, the velocity structure of the Gorda uppermost mantle is remarkably consistent with predictions from a conductive cooling model (attached figure). Limited deformation at mantle depths is supported by seismic anisotropy measurements that show the fast-direction of P-wave propagation rotates in concert with the magnetic anomaly lineations. This rotation may be explained by local plate kinematics without internal deformation and hydration of the shallow mantle. In contrast to Gorda, the seismic velocity structure of the JdF plate does not exhibit a clear age dependence. Three pronounced mantle low-velocity zones are found along the southern edge of the JdF plate near the termini of large pseudofaults that contributed to the formation of the Blanco Transform fault. We attribute these velocity reductions to mantle alteration by seawater. We note that within the interior of the JdF plate pseudofaults do not appear as uniformly slow features in our seismic images. Beneath the central and northern JdF plate, P-wave speeds are ~7.7 km/s out to ~4-5 Myr before abruptly increasing to ~7.9 km/s. Curiously, this transition occurs near the onset of mantle downwelling inferred from teleseismic body wave tomography and attenuation suggesting that mantle flow dynamics may influence the structure of young oceanic lithosphere. Lastly, we note that our results do not suggest a relationship between the structure of the uppermost slab mantle and segmentation of the Cascadia megathrust.

New relative paleointensity results from mafic lava flows erupted in quick succession during four Neogene geomagnetic reversals show that volcanic transition zones can provide a favorable setting for the pseudo-Thellier technique. The most compelling data are from a normal-to-reverse (N-R) transition zone in the 4 my old basaltic lava flows of the Olokele Formation on Kauai (Hawaii). Following stepwise alternating field (AF) demagnetization of each sample’s natural remanent magnetization, an anhysteretic remanent magnetization (ARM) was imparted in a 50 uT bias field and then AF demagnetized. Very similar behavior of the 35 mT to 90 mT coercivity fractions suggest that the NRM (interpreted to be a primary thermoremanent magnetization (TRM)) and ARM reside in the same subpopulation of magnetic grains. With the ARM intensity serving as an analog for TRM susceptibility, the 35 mT-90 mT TRM/ARM ratios provide a relative measure of the ancient field intensity. Good correlation of flow-mean TRM/ARM ratios with a small set of double-heating paleointensities from companion samples allows an approximate scaling of the TRM/ARM ratios to absolute intensity. As the geomagnetic polarity switched, the field strength apparently dropped by 91% compared to the maximum recorded by the flows. This decrease is comparable to that observed in other paleomagnetic studies and numerical simulations. During an interval of NE-down directional stasis recorded by a succession of 10 flows in the lower half of the section, the geomagnetic intensity rose to over 20 uT and then decreased to near 5 uT. This distinctive behavior could mark the waxing and waning of a stationary, inward-directed flux patch on the core mantle boundary centered NE of Kauai. Within-flow variability of relative paleointensity was higher in two other Pliocene transition zones on Kauai (both R-N), and in the R-N transition recorded by 15.2 my old lavas in the Sheep Creek Range (Nevada). Nevertheless, all three records document a reduction in the ancient geomagnetic field intensity similar in magnitude to that seen in the Olokele flows. The relative uniformity of magnetic mineralogy may help explain why the pseudo-Thellier technique was able to capture the large transitional intensity changes recorded by these rapidly-erupted flow sequences.

Northern Mexico is characterized by semiarid climate, where limited precipitation restricts crop production. Therefore, production needs efficient irrigation techniques. Agriculture is a high water consumption activity that in order to become more sustainable, demands knowledge of irrigation efficiencies at the regional scale. In this work we present a method to estimate irrigation efficiencies of croplands based on the crops’ water demand obtained with remote sensing data. The study site is located in an agricultural valley in northern Mexico in an area of cornfields with approximately 47,000 ha under irrigation that lies on top of an overexploited aquifer with a sustained declining water table (averaging 2m/year of drawdown). Using Landsat 8 derived imagery from the METRIC-EEFLUX site for the period between May 16 (emergence season) to Nov 24 (harvest season) during the 2017 agricultural cycle, the Crop coefficient (Kc), the reference Evapotranspiration (ET0) and the actual Evapotranspiration (Eta) were obtained. To obtain daily values of ETa in between the 16 day Landsat images interval, we used Kc obtained from its relation with a normalization of the enhanced vegetation index (EVI), and ET0 calculated using Penmann-Montheit fed with meteorological data from weather stations in the vicinity of the area. Irrigation efficiency was calculated using the quotient between ETa and water applied during the agricultural cycle measured with volumetric gauges at the outlet of the irrigation systems. For this study we monitored 5 parcels of corn with different irrigation systems: two parcels with drip irrigation, one with sprinkler irrigation and two with furrow irrigation. Results from the irrigation efficiencies ranged from 47 % to 71 % and depend on factors like parcel dimensions, irrigation schemes, scheduling and its spatial uniformity. Crop yield data is used to discuss the impacts of these factors on the irrigation efficiencies and the implications of different water use strategies for the sustainability of water resource-compromised regions. This methodology can be replicated in extensive areas requiring knowledge of irrigation efficiencies for more sustainable water management.

Climate change is a primary factor influencing alterations in watershed hydrology. Associated changes in temperature and precipitation can influence the fate and transport of non-point source pollution within a watershed, which complicates the application of best management practices (BMPs) for pollution mitigation. Understanding the sensitivity of BMP implementation as climate change is critical for proper management of water resources. The objective of this study is to understand the effects of BMPs on sediment and nutrient yields in the Meramec River watershed in eastern Missouri, U.S.A due to changes in climate. The Soil and Water Assessment Tool (SWAT) was used to model the flow, sediment and nutrient yields across the watershed. Multi-site calibration (1996-2012) and validation (1981-1995; 2012-2014) gave varied results, ranging from very good to acceptable, for the monthly flow, sediment load, total nitrogen (TN) and total phosphorus (TP). Various BMPs were implemented into the calibrated model in conjunction with climate data from four Coupled Model Intercomparison Project Phase 5(CMIP5) projections to estimate the effects of climate change on watershed yields. Implemented BMPs include riparian buffers, vegetated filter strips, terrace, grassed waterway, and tillage. BMPs were implemented in subwatersheds with high sediment and nutrient outputs as well as relatively high ecological value. Results indicate that BMPs could achieve reductions in a range from 2 to 76% for sediment loss, 1 to 64% for TN loss, and 5 to 54% for TP loss. Among the individual BMPs assessed, vegetated filter strips were most effective when considering the reduction in sediment and nutrient loads. This study highlights the effectiveness of a range of BMPs in reducing the sediment and nutrient loads and provides quantitative measures for determining the most effective individual BMP and the optimal combination of BMPs based on current and future climate scenarios.

Permafrost regions store an estimated half of the global belowground organic carbon pool and twice the global atmospheric carbon level. A warming climate results in increased carbon gas emission, therefore knowing more about the amount and composition of organic carbon stored in permafrost regions is crucial for understanding feedbacks on global climate change. Using the Yukon-Kukskowim (YK) Delta, Alaska as a study site, we quantified belowground carbon pools and their potential vulnerability to release into the atmosphere as greenhouse gasses. We identified relevant landcover classes (burned and unburned upland peat plateaus, wetlands, ponds/lakes) in the YK Delta, from which we quantified total belowground carbon pools (30cm) and assessed the composition of the organic matter using Fourier-transform infrared spectroscopy. To characterize the size and distribution of soil carbon pools in the YK Delta, we built a Random Forest Machine Learning model that mapped the spatial distribution of soil carbon to a depth of 30 cm over a 1910 km2 watershed. The map product was produced in Google Earth Engine and used covariates that include, but are not limited to, Worldview2 high-resolution optical imagery (2m), ArcticDEM (5m), and Sentinel-2 level 1C multispectral imagery (10 m), including NDVI. We found substantial variation across landcover classes in soil characteristics that affect organic matter vulnerability, including gravimetric water content, thaw depth, bulk density, and percent carbon. Compared to upland areas, thaw depths were significantly deeper in wetlands and lakes, where we detected no surface permafrost (to 1m). Soil carbon content (%) was greatest in moss-dominated wetlands; however, these areas also had the lowest bulk density. Carbon pools and organic matter characteristics also varied between burned and unburned areas. Therefore, we expect that carbon vulnerability varies by landcover class and that future carbon emissions are driven by total carbon pools, thaw depths, and composition of the carbon stored in organic matter pools. These carbon pool and vulnerability maps will contribute to better understanding the impacts of subarctic warming and are critical for developing a more accurate assessment of carbon cycling feedbacks from permafrost regions on global climate change.

NOAA/National Ocean Service’s (NOS) Center for Operational Oceanographic Products and Services (CO-OPS) provides users with real-time currents at more than sixty stations, currents predictions at thousands of historic and active stations, and operational currents nowcast and near-term forecast information in navigable estuaries, harbors, rivers, and coastal regions of the United States as an integral part of its safe navigation mission. CO-OPS performs at least one current survey each year to update currents predictions in regions of particular interest to stakeholders. NOS’ Operational Forecast Systems (OFS) operate and maintain fully 3-D hydrodynamic models that provide regional nowcast and forecast (48-60 hours) guidance for water levels, currents, salinity, and temperature. By combining the information available from real-time observations, current surveys, historic current predictions, and OFS output, both the tidal current predictions and the OFS forecast products can be improved. Tidal current predictions are traditionally generated based on analysis of at least one month of six-minute observation data obtained from a physically deployed current meter using harmonic least squares techniques to resolve tidal constituents. By using longer time series and traditional techniques combined with additional statistical methods, a more accurate representation of the tidal flow and a more exact match to the shape of the tidal current curve is obtained. By applying these methods to long-term OFS output at locations where long-term physical observations also exist, tidal current predictions based on model data within the model domain can be verified. Once verified, the number of available “virtual stations” exponentially increases the repository of tidal current predictions. Users can choose any location of interest and receive tidal current predictions that can be incorporated into integrated, user-friendly navigation products and tools. We will evaluate this technique in the lower Chesapeake Bay using output from the Chesapeake Bay Operational Forecast System (CBOFS) and real-time currents data.

Wind is an important driver of large-scale ocean currents, imparting momentum into the ocean at the sea surface. In particular, strong westerly winds help to drive the Antarctic Circumpolar Current, which of key importance for the global climate system. Over the past decades observations established that the strength of the westerlies over the Southern Ocean has increased as a result of climate change forcing. This increase is consistent with global climate model simulations. The future climate state depends strongly on how will the Antarctic Circumpolar Current respond to this strengthening. Eddy saturation is a theoretical regime where the transport of the current remains insensitive to the strengthening of the westerlies. Instead, the strengthening of the westerlies energizes transient eddies. Both satellite observations and numerical simulations suggest that the Antarctic Circumpolar Current is close to the eddy saturated limit. Traditionally eddy saturation has been attributed to baroclinic processes, but recent work suggests that barotropic processes that involve, e.g., standing meanders of the Antarctic Circumpolar Current, can also be responsible for producing eddy-saturated states. Here, we discus the different physical entities of the“usual” baroclinic eddy saturation as well as the recent notion of barotropic eddy saturation. We assess the relative importance of barotropic and baroclinic processes in producing eddy-saturated states using numerical simulations of primitive equations in an idealized setup. Lastly, we discuss potential implications these processes have on global ocean modeling.

Excess sediment is one of the main agents of water pollution, affects the aquatic ecosystem and causes siltation problems in reservoirs and rivers. Bottom sediments are coarse and easily deposited, being the major responsible for morphological alterations in rivers. Therefore, is important to estimate the amount of sediment transported in other to establish mitigation strategies and recovery of affected areas. There are several methodologies for estimating bedload transport: equations, numerical modeling, direct physical sampling, and indirect method measuring dune tracking. Most studies measure bedload transport using the equipment Helley-Smith, generally taken as reference value for other methods. However, Helley-Smith causes changes in the flow field, often resulting in overestimates in sand bed rivers. Those overestimates were not yet described and quantified in detail. This article tries to solve this gap by observing the Helley-Smith sampler at the time of sampling. For this, we used a video camera recording processed by Particle Image Velocimetry (PIV) technique to qualitatively evaluate changes that the intrusive sampler causes in the displacement of bottom sediments in a sand bed river. When the sampler was properly allocated to the bottom, PIV resulting velocity maps of bedload particle transport identified the acceleration of the bottom particles as they approached the mouth of the sampler. We also noticed areas of convergence and vorticity of the sediments towards the sampler’s mouth, which may overestimate sampling. When the sampler’s mouth was disconnected from the bed due to the morphology of the bottom, we find regions of divergence in the displacement of the sediments creating unrealistic results for bedload transport analysis. In addition, the presence of organic matter can be underestimated, which causes difficulties in analyzing the quality of the collections because it is not possible to guarantee an equity in the positioning of the equipment at the bottom of the channel. We thus recommend complementation Helley-Smith measurements with surrogate methods, for example such as using ADCPs or optical methods, as the one described here.

Inlet change along the Virginia barrier islands has been studied on an individual inlet basis. This study evaluated the ten inlets both individually and as a group. Evaluating the inlets as a group allows the discovery of inlet change patterns among the inlets. Inlet width was measured from satellite and aerial images. Width is the straight-line distance from the northernmost fast land to southernmost fast land. Measurements spanned from July 1999 to April 2018 with a frequency of four to eight width measurements per year. Total width change to 2018 was 2 percent to 357 percent. The largest change was to Great Machipongo Inlet. The inlet widened from approximately 800 meters wide in 1999 to 3645 meters wide in 2018. This widening effectively splits the remaining nine inlets into two groups. Inlet widening patterns of the two groups are high rates for the first three or four inlets and a very low rate for the final inlet of the group. Wind direction change also plays a significant role in net inlet widening. Inlet widening has not abated and wider inlets will allow larger waves to affect environmentally and commercially important areas to the west of the barrier island/inlet system.

Along sandy coasts, the seaward expansion of dunes starts with the development of embryonic dunes. Vegetation is crucial for their initiation and the subsequent increase in dune height and volume when sediment supply is sufficient. During severe storms, the plants’ tolerance to and recovery from hydrodynamic disturbances, such as exposure to saline water during high water levels and their (partial) removal during storms, is vital to the long-term (months to years) resilience of the dune building process. Accordingly, areas with high embryo dune abundance have been correlated to wider beaches, attributed both to increased wind-driven sediment supply and increased wave attenuation during storms. Recent observations have shown that alongshore variations in subtidal sandbar morphology may also lead to variations in wave attenuation and foredune erosion, following a series of extreme storms. With our research we aim to determine whether subtidal bar characteristics play a role in long-term (months to years) embryo dune development. We first analysed a data set of 112 annual bathymetric profiles (spaced 250 m alongshore) and topographic (airborne Lidar) measurements in addition to observations of embryo dune presence derived from aerial photographs, spanning 50 km along the Dutch coast from 2010 to 2016. Embryo dune area extraction was done by supervised classification of vegetation pixels on the beach. Using a linear regression model, we found that profiles with a more seaward vegetation extent significantly correlated to shallower subtidal bars, in particular during stormy years. Second, to study the timing and alongshore variability of individual erosion events in more detail, we analysed 10 years (2005-2015) of half-hourly images of a 4-km stretch of the same coast, near Egmond aan Zee, in addition to the annual data. These images provide unique observations of the entire bar-beach-dune system, allowing for the concurrent analysis of bar morphology, embryo dune areas and, crucially, embryo dune exposure to saline water and wave action during storm events. At the conference, we will further explain the observed spatial and temporal (storm-driven) variability in embryo dune development.

Vertical electrical sounding (VES) surveys were performed on the Chukchi Sea ice near Utqiagvik (ne’ Barrow), AK in March, 2018, using a capacitively coupled resistivity array. The purpose of this study was to determine the effectiveness of the VES method in determining the thickness of the sea ice and potentially the depth to the sea floor. The array was deployed in an atypical set-up, with the transmitter and a single receiver being moved incrementally further from a central point. The results of three trials from 2018 are presented, along with the re-analysis of data from two trials from March, 2016. The VES data were analyzed using “cumulative resistivity” plots, from which ice thicknesses were determined. Ice depths were measured by drilling through the ice at the central point of the array. The VES and drill thicknesses agree to within a few percent for the ≲1m-thick ice. The VES plots may also indicate differences in ice composition as it transitions from the solid uppermost ice down to seawater.

This study investigates how marine resource users are impacted by the offshore Block Island Wind Farm (BIWF). In the summer and fall of 2017, we conducted semi-structured interviews with recreational and commercial fishermen that use the area around the BIWF. We asked fishermen about their perceptions of changes in the ecology of the area during and after the offshore wind turbines were constructed, and how their behavior and use of the area changed in response to the construction and post-construction of the wind farm. We interviewed over 20 fishermen, mainly based out of Block Island or Point Judith, Narragansett. Analysis of the interview data suggests that some fishermen view the wind farm as a positive development for fishing in the area, while others have mixed feelings or dislike the project. Perceptions of changes in the BIWF area seem to vary within and among commercial and recreational fishermen. In addition, comparison of interview data with ecological data on fish and lobster in the BIWF area before, during and post-construction highlights areas of agreement and disagreement between perceived and observed changes. These results provide important information on how offshore wind farms in the Northeast are impacting marine resource users in terms of perceived and observed impacts. Open Access Paper: https://www.frontiersin.org/articles/10.3389/fmars.2018.00439/full

Spanning a period of more than 15 years, the Landsat Legacy Project Team researched, complied and published, in late 2017, Landsat's Enduring Legacy that describes the myriad of factors that surround the nearly half-century of monitoring the Earth's surface with Landsat. Born of technologies that evolved from the World War II, Landsat not only pioneered global land monitoring but, in the process, drove innovation in digital imaging technologies and encouraged development of global imagery archives. Access to this imagery led to early breakthroughs in natural resources assessments, particularly for agriculture, forestry, and geology. The technical and political aspects of the remote sensing revolution led by Landsat were not simple or straightforward. Early conflicts between civilian and defense satellite remote sensing users gave way to disagreements over whether the Landsat system should be a public service or a private enterprise. Only the combined engagement of civilian and defense organizations ultimately saved this pioneer satellite land monitoring program from termination. With the emergence of 21st century Earth system science research, coupled with greatly enhanced data computing, storage and transfer capabilities, the full value of the Landsat concept and its continuous, calibrated nearly half-century global archive has been recognized and embraced. The attempts to privatize Landsat had dramatic negative impacts on the collection, availability, and use of the data. These impacts should inform deliberations on the future of the Landsat program moving toward a Sustained Land Imaging program following Landsat 9. Discussion of Landsat's future continues, but its heritage will not be forgotten.

Human-mediated climate change over the past century has made significant impacts on global ecosystems and biodiversity including accelerating redistribution of the geographic ranges of species. In mountainous regions, the transition zone from continuous closed-canopy subalpine forests to treeless alpine tundra areas at higher elevations is commonly referred to as ‘Alpine Treeline Ecotone’ (ATE). Globally, warming climate is expected to drive the ATE upslope, which could lead to negative impacts on local biodiversity and modify ecosystem function. However, existing studies rely primarily on field-based data which are difficult and time consuming to collect. In this research, we define three critical characteristics of the ATE including 1) an abrupt spatial shift in vegetative activity as elevation varies, 2) reduction in vegetative activity as elevation increases, and 3) vegetative activity is at an intermediate level. Using the geospatial tools provided by Google Earth Engine, we construct an index (ATEI) to identify areas with the three ATE features based on the image gradients of vegetative activity and elevation datasets. Based on the ATEI and Google Earth imagery in 115 Landsat pixels, we establish a Logistic regression model to estimate the probability of whether or not a sampled pixel is located within the ATE. The prediction accuracy is approximately 80%. Furthermore, the ATEI-estimated ATE elevation is strongly correlated (r = 0.96) with a set of field-based data at 20 sampling sites from across the region. Based on the average annual ATEIs from 2009 to 2011, we estimate the average ATE elevation for each mountain range in the western U.S. The result varies from 1,183 m to 3,584 m. The detection metric developed in this study facilitates monitoring the geographic location and potential shifts of ATEs as well as the general impact of climate change in mountainous regions during recent decades. We also expect this approach to be useful in monitoring other ecosystem boundaries.

A system capable of reliably detecting catastrophic landslides and centimeter movement in land mass could save lives and offers landowners valuable information about gradual changes in soil displacement on their land. With precise acceleration and relative positioning data collected from an accelerometer and a set of GPS receivers, a system can be designed to detect subtle changes in sensor position due to land movement. With the rapid production of new microprocessors and greater memory storage capabilities the limits of microcontroller systems are continually expanding. The Slide Sentinel project offers landowners a low-cost alternative to commercial equipment consisting of a network of remote low power sensors that detect fast linear slides and eventually lower soil movements such as creep. Long range low-power (LoRa) radio connections on these sensor nodes wirelessly transmit three-dimensional acceleration, Real Time Kinematic (RTK) GPS coordinates, and sudden shift alerts to a common base station where they are exported to an online spreadsheet to be processed remotely.

Several winters of the 2010s have brought to many midlatitude regions periods of extreme cold relative to the past few years and even decades. Further, it is suggested that melting of Arctic sea ice has increased the likelihood of persistent extreme weather conditions in the northern midlatitudes and the number of cold winter days. Here, estimates of warming in annual minimum temperature are updated and extended to all land areas where station temperature records are available, with emphasis on the midlatitudes. Annual minimum temperatures have warmed faster than mean temperatures in seasonally cold land regions and have already exceeded a 2 K warming threshold over the midlatitudes, but have warmed at about the same rate as mean temperatures in tropical climates. Recent regionally cold winters did not significantly deviate from the established warming trend and were within the range of interannual variability seen in the past. These findings have implications for contextualizing extreme winter weather, validating climate model projections of the consequences of sea ice loss, and guiding adaptation to shifting hardiness zones of perennial cultivars and the spread of pest and invasive species.

Unmanned aerial vehicles (UAV) have been increasingly used for field data collection and remote sensing purposes. Their ease of use, ability to carry sensors and cameras, low cost, and precise maneuverability and navigation makes them a versatile tool for a field researcher. Procedures and instrumentation to use UAVs in the field are largely undefined, especially for atmospheric and hydrologic applications. A field study was conducted to test the UAV’s ability to collect atmospheric data in order to locate and analyze the canopy boundary layer (CBL) above a Costa Rican tropical montane rainforest. This study aims to give further insight on the changes of the CBL throughout the day and for atmospheric comparison to land development. Through the study, it was found that there was little previously defined procedures and preferred instrumentation that directly applied to the UAV field study. Because of this, the methodology of using an UAV for atmospheric and CBL remote sensing and data collection was developed and refined by testing and comparing precision and performance of sensors and executing systematic flight patterns throughout the day. The UAV allowed for quick and specific access to sampling locations and for all of the variables to be measured by sensors over vertical profiles. Flights were scheduled at different locations throughout the day over the Texas A&M Soltis Center and surrounding forest in San Isidro, Costa Rica. Vertical profiles were also measured over the Soltis Center grounds to determine how development has affected the presence of the CBL. The UAV was successful in gathering data above the forest canopy and the Soltis Center at varying elevations during clear and cloudy conditions. The procedure produced reliably consistent vertical profiles over small domains in space and time, validating the general approach. The technique also identified unique profiles at spatially and temporally distinct sample sites including response to meteorological events. These findings suggest a healthy ability to diagnose CBL characteristics of interest. It was also found that there is a distinct increase in temperature and dew point over land development when compared to over forest. Future studies include flights at other locations and determining preferred instrumentation for UAV atmospheric data collection.