Spatial Patterns and Trends in Surface Air Temperatures and Implied Changes in Atmospheric Moisture Across the Hawaiian Islands, 1905–2017

2020 ◽  
Vol 125 (2) ◽  
Author(s):  
A. K. Kagawa‐Viviani ◽  
T. W. Giambelluca
Keyword(s):  
Spatial Patterns ◽  
Hawaiian Islands ◽  
Atmospheric Moisture ◽  
Air Temperatures

scholarly journals A Comparative Study of Atmospheric Moisture Recycling Rate between Observations and Models

2018 ◽  
Vol 31 (6) ◽  
pp. 2389-2398 ◽  
Author(s):  
Angela Kao ◽  
Xun Jiang ◽  
Liming Li ◽  
James H. Trammell ◽  
Guang J. Zhang ◽  
...  
Keyword(s):  
Water Vapor ◽  
Spatial Patterns ◽  
Cmip5 Models ◽  
Recycling Rate ◽  
Short Time Scale ◽  
Atmospheric Moisture ◽  
Important Indicator ◽  
Moisture Recycling ◽  
Short Time

Precipitation and column water vapor data from 13 CMIP5 models and observational datasets are used to analyze atmospheric moisture recycling rate from 1988 to 2008. The comparisons between observations and model simulations suggest that most CMIP5 models capture two main characteristics of the recycling rate: 1) long-term decreasing trend of the global-average maritime recycling rate (atmospheric recycling rate over ocean within 60°S–60°N) and 2) dominant spatial patterns of the temporal variations of the recycling rate (i.e., increasing in the intertropical convergence zone and decreasing in subtropical regions). All models, except one, successfully simulate not only the long-term trend but also the interannual variability of column water vapor. The simulations of precipitation are relatively poor, especially over the relatively short time scales, which lead to the discrepancy of the recycling rate between observations and the CMIP5 models. Comparisons of spatial patterns also suggest that the CMIP5 models simulate column water vapor better than precipitation. The comparative studies indicate the scope of improvement in the simulations of precipitation, especially for the relatively short-time-scale variations, to better simulate the recycling rate of atmospheric moisture, an important indicator of climate change.

scholarly journals Spatial patterns of surface hoar properties and incoming radiation on an inclined forest opening

2011 ◽  
Vol 57 (202) ◽  
pp. 355-366 ◽  
Author(s):  
Eric R. Lutz ◽  
Karl W. Birkeland
Keyword(s):  
Shear Strength ◽  
Layer Thickness ◽  
Spatial Patterns ◽  
Spatial Models ◽  
Shortwave Radiation ◽  
Hazard Evaluation ◽  
Avalanche Hazard ◽  
Incoming Radiation ◽  
Air Temperatures ◽  
Physically Based

AbstractAvalanche hazard evaluation relies in part on representative snowpack stability observations. Thus, understanding the spatial patterns of snowpack instabilities and their environmental determinants is crucial. This case study integrates intensive field observations with spatial modeling to identify associations between incoming radiation, surface hoar development and its subsequent shear strength across an inclined forest opening. We examined a buried surface hoar layer in southwest Montana, USA, over five sampling days, collecting 824 SnowMicroPen resistance profiles and performing 352 shear frame tests. Spatial models of incoming long- and shortwave radiation were generated for the surface hoar formation period using modeled hemispheric sky visibility, physically based parameters and the Bird Clear Sky Radiation Model in a Geographic Information System. Before burial, the surface hoar persisted despite moderate winds and relatively high air temperatures. The buried surface hoar layer thickness varied between 3 and 21 mm within a distance of 30 m. Modeled incoming radiation explained spatial variations in layer thickness and shear strength. In areas exposed to large amounts of radiation, the surface hoar layer was strong and thin, while areas with limited incoming radiation (due to high sky visibility and shading) possessed a thicker surface hoar layer that sheared more easily. This demonstrates the usefulness of microclimate modeling for slope-scale avalanche hazard evaluation. We also identify that over the 3 week sample period, strengthening occurred without thinning of the surface hoar layer.

scholarly journals Patterns in artisanal coral reef fisheries reveal best practices for monitoring and management

2017 ◽  
Author(s):  
David G Delaney ◽  
Lida T Teneva ◽  
Kostantinos A Stamoulis ◽  
Jonatha L Giddens ◽  
Haruko Koike ◽  
...  
Keyword(s):  
Food Security ◽  
Coral Reef ◽  
Spatial Patterns ◽  
Hawaiian Islands ◽  
Fishing Effort ◽  
Local Communities ◽  
Accurate Information ◽  
Catch Per Unit Effort ◽  
Regional Patterns ◽  
Coral Reef Fisheries

Sustainable fisheries management is key to restoring and maintaining ecological function and benefits to people, but it requires accurate information about patterns in resource use, particularly fishing pressure. In most coral reef fisheries and other data-poor contexts, obtaining such information is challenging and remains an impediment to effective management. We developed the most comprehensive regional view of shore-based fishing effort and catch for the Hawaiian Islands to show detailed fishing patterns from across the main Hawaiian Islands (MHI). We reveal these regional patterns through fisher “creel” surveys conducted through collaborative efforts by local communities, state agencies, academics, and environmental organizations, at 18 sites and comprising >10,000 hr of monitoring across a range of habitats and human influences throughout the MHI. Here, we document spatial patterns in nearshore fisheries catch, effort, catch rates (i.e., catch-per-unit-effort [CPUE]), and catch disposition (i.e., use of fish after catch is landed). Line fishing was consistently the most commonly employed gear type (94%), followed by net fishing. The most efficient gear types (i.e., higher CPUE) were spear (0.64 kg hr-1), followed closely by net (0.61 kg hr-1), with CPUE for line (0.16 kg hr-1) 3.9 times lower than spear and 3.7 times lower than net. Creel surveys also reveal rampant illegal fishing activity across the studied locations. Surprisingly, overall, most of the catch was not sold, but rather retained for home consumption or given away to extended family, which indicates that cultural and food security may be stronger drivers of fishing effort than commercial exploitation for nearshore coral reef fisheries in Hawai‘i. Increased monitoring of spatial patterns in nearshore fisheries can inform targeted management, in order to maintain these fisheries for local communities’ food security, cultural, and ecological value.

scholarly journals Modelling the transfer of supraglacial meltwater to the bed of Leverett Glacier, southwest Greenland

2014 ◽  
Vol 8 (4) ◽  
pp. 4243-4280 ◽  
Author(s):  
C. C. Clason ◽  
D. W. F. Mair ◽  
P. W. Nienow ◽  
I. D. Bartholomew ◽  
A. Sole ◽  
...  
Keyword(s):  
Spatial Patterns ◽  
Greenland Ice Sheet ◽  
Temporal And Spatial Patterns ◽  
Distributed Modelling ◽  
Supraglacial Lakes ◽  
Ice Surface ◽  
Air Temperatures ◽  
Spatially Distributed ◽  
Temporal And Spatial ◽  
Efficient Transfer

Abstract. Meltwater delivered to the bed of the Greenland Ice Sheet is a driver of variable ice-motion through changes in effective pressure and enhanced basal lubrication. Ice surface velocities have been shown to respond rapidly both to meltwater production at the surface and to drainage of supraglacial lakes, suggesting efficient transfer of meltwater from the supraglacial to subglacial hydrological systems. Although considerable effort is currently being directed towards improved modelling of the controlling surface and basal processes, modelling the temporal and spatial evolution of the transfer of melt to the bed has received less attention. Here we present the results of spatially-distributed modelling for prediction of moulins and lake drainages on the Leverett Glacier in south-west Greenland. The model is run for the 2009 and 2010 ablation seasons, and for future increased melt scenarios. The temporal and spatial patterns of modelled lake drainages are qualitatively comparable with those seen from analyses of satellite imagery. The modelled timings and locations of delivery of meltwater to the bed match well with observed temporal and spatial patterns of ice surface speed ups. This is particularly true for the lower catchment (< 1000 m a.s.l.) where both the model and observations indicate that the development of moulins is the main mechanism for the transfer of surface meltwater to the bed. At higher elevations (e.g. 1250–1500 m a.s.l.) the development and drainage of supraglacial lakes becomes increasingly important. At these higher elevations, the delay between modelled melt generation and subsequent delivery of melt to the bed matches the observed delay between the peak air temperatures and subsequent velocity speed ups. Although both moulins and lake drainages are predicted to increase in number for future warmer climate scenarios, the lake drainages play an increasingly important role in both expanding the area over which melt accesses the bed and in enabling a greater proportion of surface melt to reach the bed.

Role of the Atmospheric Moisture Budget in Defining the Precipitation Seasonality of the Great Lakes Region

2021 ◽  
Vol 34 (2) ◽  
pp. 643-657
Author(s):  
Samar Minallah ◽  
Allison L. Steiner
Keyword(s):  
Great Lakes ◽  
Spatial Patterns ◽  
Moisture Transport ◽  
Transport Processes ◽  
Great Lakes Region ◽  
Moisture Budget ◽  
Atmospheric Moisture ◽  
Precipitation Seasonality ◽  
Atmospheric Moisture Budget

AbstractPrecipitation in the Great Lakes region has a distinct seasonal cycle that peaks in early summer, followed by a decline in August and a secondary peak in September. This seasonality is often not captured by models, which necessitates understanding of the driving mechanisms to ascertain the model biases. This study analyzes the atmospheric moisture budget using reanalysis datasets to assess the role of regional evapotranspiration and moisture influx from remote origins in defining the precipitation seasonality, and to understand how the Great Lakes modulate spatial patterns and magnitudes of these components. Specifically, the land–water thermal contrast yields large seasonal variations in the evaporative fluxes and creates distinctive localized spatial patterns of moisture flux divergence. We find considerable month-to-month variations in both evapotranspiration and the net moisture transport through the boundaries, where they play a cooperative (contrasting) role in amplifying (dampening) the moisture content available for precipitation and total precipitable water. Our seasonal analysis suggests that the misrepresentation of the budget quantities in models, for example, in simulation of moisture transport processes and parameterization schemes, can result in an anomalous precipitation behavior and, in some cases, violation of the atmospheric moisture mass balance, resulting in large residual magnitudes. We also identify conspicuous differences in the representation of moisture budget components in the various reanalyses, which can alter their representation of the regional hydroclimates.

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