Shuttle landing facility cloud cover study: Climatological analysis and two tenths cloud cover rule evaluation

The two-tenths cloud cover rule in effect for all End Of Mission (EOM) STS landings at the Kennedy Space Center (KSC) states: 'for scattered cloud layers below 10,000 feet, cloud cover must be observed to be less than or equal to 0.2 at the de-orbit burn go/no-go decision time (approximately 90 minutes before landing time)'. This rule was designed to protect against a ceiling (below 10,000 feet) developing unexpectedly within the next 90 minutes (i.e., after the de-orbit burn decision and before landing). The Applied Meteorological Unit (AMU) developed and analyzed a database of cloud cover amounts and weather conditions at the Shuttle Landing Facility for a five-year (1986-1990) period. The data indicate the best time to land the shuttle at KSC is during the summer while the worst time is during the winter. The analysis also shows the highest frequency of landing opportunities occurs for the 0100-0600 UTC and 1300-1600 UTC time periods. The worst time of the day to land a shuttle is near sunrise and during the afternoon. An evaluation of the two-tenths cloud cover rule for most data categorizations has shown that there is a significant difference in the proportions of weather violations one and two hours subsequent to initial conditions of 0.2 and 0.3 cloud cover. However, for May, Oct., 700 mb northerly wind category, 1500 UTC category, and 1600 UTC category there is some evidence that the 0.2 cloud cover rule may be overly conservative. This possibility requires further investigation. As a result of these analyses, the AMU developed nomograms to help the Spaceflight Meteorological Group (SMG) and the Cape Canaveral Forecast Facility (CCFF) forecast cloud cover for EOM and Return to Launch Site (RTLS) at KSC. Future work will include updating the two tenths database, further analysis of the data for several categorizations, and developing a proof of concept artificial neural network to provide forecast guidance of weather constraint violations for shuttle landings

Basin structure of optimization based state and parameter estimation

Most data based state and parameter estimation methods require suitable initial values or guesses to achieve convergence to the desired solution, which typically is a global minimum of some cost function. Unfortunately, however, other stable solutions (e.g., local minima) may exist and provide suboptimal or even wrong estimates. Here we demonstrate for a 9-dimensional Lorenz-96 model how to characterize the basin size of the global minimum when applying some particular optimization based estimation algorithm. We compare three different strategies for generating suitable initial guesses and we investigate the dependence of the solution on the given trajectory segment (underlying the measured time series). To address the question of how many state variables have to be measured for optimal performance, different types of multivariate time series are considered consisting of 1, 2, or 3 variables. Based on these time series the local observability of state variables and parameters of the Lorenz-96 model is investigated and confirmed using delay coordinates. This result is in good agreement with the observation that correct state and parameter estimation results are obtained if the optimization algorithm is initialized with initial guesses close to the true solution. In contrast, initialization with other exact solutions of the model equations (different from the true solution used to generate the time series) typically fails, i.e. the optimization procedure ends up in local minima different from the true solution. Initialization using random values in a box around the attractor exhibits success rates depending on the number of observables and the available time series (trajectory segment).Comment: 15 pages, 2 figure

The evaluation of ASOS for the Kennedy Space Center's Shuttle Landing Facility

This report documents the Applied Meteorology Unit's (AMU) evaluation of the effectiveness and utility of the Automated Surface Observing System (ASOS) in terms of spaceflight operations and user requirements. In particular, the evaluation determines which of the Shuttle Landing Facility (SLF) observation requirements can be satisfied by ASOS. This report also includes a summary of ASOS' background, current configuration and specifications, system performance, and the possible concepts of operations for use of ASOS at the SLF. This evaluation stems from a desire by the Air Force to determine if ASOS units could be used to reduce the cost of SLF meteorological observations

Report on the comparison of the scan strategies employed by the Patrick Air Force Base WSR-74C/McGill radar and the NWS Melbourne WSR-88D radar

The objective of this investigation is to determine whether the current standard WSR-88D radar (NEXRAD) scan strategies permit the use of the Melbourne WSR-88D to perform the essential functions now performed by the Patrick Air Force Base (PAFB) WSR-74C/McGill radar for evaluating shuttle weather flight rules (FR) and launch commit criteria (LCC). To meet this objective, the investigation compared the beam coverage patterns of the WSR-74C/McGill radar located at PAFB and the WSR-88D radar located at the Melbourne National Weather Service (NWS) Office over the area of concern for weather FR and LCC evaluations. The analysis focused on beam coverage within four vertical 74 km radius cylinders (1 to 4 km above ground level (AGL), 4 to 8 km AGL, 8 to 12 km AGL, and 1 to 12 km AGL) centered on Kennedy Space Center (KSC) Launch Complex 39A. The PAFB WSR-74C/McGill radar is approximately 17 km north-northeast of the Melbourne WSR-88D radar. The beam coverage of the WSR-88D using VCP 11 located at the Melbourne NWS Office is comparable (difference in percent of the atmosphere sampled between the two radars is 10 percent or less) within the area of concern to the beam coverage of the WSR-74C/McGill radar located at PAFB. Both radars provide good beam coverage over much of the atmospheric region of concern. In addition, both radars provide poor beam coverage (coverage less than 50 percent) over limited regions near the radars due to the radars' cone of silence and gaps in coverage within the higher elevation scans. Based on scan strategy alone, the WSR-88D radar could be used to perform the essential functions now performed by the PAFB WSR-74C/McGill radar for evaluating shuttle weather FR and LCC. Other radar characteristics may, however, affect the decision as to which radar to use in a given case

Testing glacial isostatic adjustment models of last-interglacial sea level history in the Bahamas and Bermuda

Part of the spatial variation in the apparent sea-level record of the last interglacial (LIG) period is due to the diverse response of coastlines to glacial isostatic adjustment (GIA) processes, particularly where coastlines were close to the Laurentide Ice Sheet during the past two glacial periods. We tested modeled LIG paleo-sea levels on New Providence Island (NPI), Bahamas and Bermuda by investigating emergent coral patch reefs and oolitic/peloidal beach deposits. Corals with closed-system histories collected from patch reefs on NPI have ages of 128-118 ka and ooids/peloids from beach ridges have closed-system ages of 128-116 ka. Elevations of patch reefs indicate a LIG paleo-sea level of at least ~7 m to ~9 m above present. Beach ridge sediments indicate paleo-sea levels of ~5 m to ~14 m (assuming subsidence, ~7 m to ~16 m) above present during the LIG. Some, though not all of these measurements are in good agreement with GIA models of paleo-sea level that have been simulated for the Bahamas. On Bermuda, corals with closed-system histories collected from marine deposits have ages of 126-114 ka. Although coral-bearing marine deposits on Bermuda lack the precise indication of paleo-sea level provided by patch reefs and oolitic beach ridges, these sediments nevertheless provide at least a first-order estimate of paleo-sea level. Paleo-sea level records on Bermuda are consistently lower (~2 m to ~7 m) than what GIA models simulate for the LIG. The reason for the reasonable agreement with models for the Bahamas and poor agreement for Bermuda is not understood, but needs further investigation in light of the probability of a higher sea level in the near future

Trace metal distributions in sulfide scales of the seawater-dominated Reykjanes geothermal system: Constraints on sub-seafloor hydrothermal mineralizing processes and metal fluxes

Highlights • Predictable trace element enrichments and depletions in the Reykjanes system. • Boiling exerts a major influence on the enrichment of metals. • High concentrations of Au and Ag and Pb indicate accumulation in reservoir fluids. • Three quarters of the metal budget is deposited at depth or in the upflow zone. Abstract Mineral precipitation in the seawater-dominated Reykjanes geothermal system on the Mid-Atlantic Ridge, Iceland is caused by abrupt, artificially induced, pressure and temperature changes as deep high-temperature liquids are drawn from reservoir rocks up through the geothermal wells. Sulfide scales within these wells represent a complete profile of mineral precipitation through a seafloor hydrothermal system, from the deep reservoir to the low-temperature silica-rich surface discharge. Mineral scales have formed under a range of conditions from high pressures and temperatures at depth (>2 km) to boiling conditions in the upflow zone and at the surface. Consistent trace element enrichments, similar to those in black smoker chimneys, are documented: Cu, Zn, Cd, Co, Te, V, Ni, Mo, W, Sn, Fe and S are enriched at higher pressures and temperatures in the deepest scales, Zn and Cu, Bi, Pb, Ag, As, Sb, Ga, Hg, Tl, U, and Th are enriched at lower temperatures and pressures nearer to the surface. A number of elements (e.g., Co, Se, Cd, Zn, Cu, and Au) are deposited in both high- and low-pressure scales, but are hosted by distinctly different minerals. Other trace elements, such as Pb, Ag, and Ga, are strongly partitioned into low-temperature minerals, such as galena (Pb, Ag) and clays (Ga). Boiling and destabilization of metal-bearing aqueous complexes are the dominant control on the deposition of most metals (particularly Au). Other metals (e.g., Cu and Se) may also have been transported in the vapor phase. Very large enrichments of Au, Ag and Pb in the scales (e.g., 948 ppm Au, 23,200 ppm Ag, and 18.8 wt.% Pb) versus average concentrations in black smoker chimneys likely reflect that some elements are preferentially deposited in boiling systems. A mass accumulation of 5.7 t/yr of massive sulfide was calculated for one high-temperature production well, equating to metal fluxes of 1.7 t/yr Zn, 0.3 t/yr Cu, 23 kg/yr Pb, 4.1 kg/yr Ag, and 0.5 kg/yr Au. At least three quarters of the major and trace element load is precipitated within the well before reaching the surface. We suggest that a similar proportion of metals may be deposited below the seafloor in submarine hydrothermal systems where significant boiling has occurred. Mass accumulation estimations over the lifetime of the Reykjanes system may indicate significant enrichment of Zn, Pb, Au, and Ag relative to both modern and ancient mafic-dominated seafloor massive sulfide deposits, and highlights the potential for metal enrichment and accumulation in the deep parts of geothermal systems

Implementation and evaluation of the new wind algorithm in NASA's 50 MHz doppler radar wind profiler

The purpose of this report is to document the Applied Meteorology Unit's implementation and evaluation of the wind algorithm developed by Marshall Space Flight Center (MSFC) on the data analysis processor (DAP) of NASA's 50 MHz doppler radar wind profiler (DRWP). The report also includes a summary of the 50 MHz DRWP characteristics and performance and a proposed concept of operations for the DRWP

The analysis of rapidly developing fog at the Kennedy Space Center

This report documents fog precursors and fog climatology at Kennedy Space Center (KSC) Florida from 1986 to 1990. The major emphasis of this report focuses on rapidly developing fog events that would affect the less than 7-statute mile visibility rule for End-Of-Mission (EOM) Shuttle landing at KSC (Rule 4-64(A)). The Applied Meteorology Unit's (AMU's) work is to: develop a data base for study of fog associated weather conditions relating to violations of this landing constraint; develop forecast techniques or rules-of-thumb to determine whether or not current conditions are likely to result in an acceptable condition at landing; validate the forecast techniques; and transition techniques to operational use. As part of the analysis the fog events were categorized as either advection, pre-frontal or radiation. As a result of these analyses, the AMU developed a fog climatological data base, identified fog precursors and developed forecaster tools and decision trees. The fog climatological analysis indicates that during the fog season (October to April) there is a higher risk for a visibility violation at KSC during the early morning hours (0700 to 1200 UTC), while 95 percent of all fog events have dissipated by 1600 UTC. A high number of fog events are characterized by a westerly component to the surface wind at KSC (92 percent) and 83 percent of the fog events had fog develop west of KSC first (up to 2 hours). The AMU developed fog decision trees and forecaster tools that would help the forecaster identify fog precursors up to 12 hours in advance. Using the decision trees as process tools ensures the important meteorological data are not overlooked in the forecast process. With these tools and a better understanding of fog formation in the local KSC area, the Shuttle weather support forecaster should be able to give the Launch and Flight Directors a better KSC fog forecast with more confidence