He I 10830 observations of the 3N/M4.0 flare of 4 September, 1982

Hei 10830 Å spectroheliograms of a major 3N two-ribbon flare occurring in Boulder Region 3885/3886 early on 4 September, 1982 are discussed and compared with H and soft X-ray observations of the event. This flare, observed for more than 60 hr in Hei 10830, was associated with the eruption of a large filament in the active region complex, the formation of coronal holes, a long-duration soft X-ray event, and was the probable source of a earthward coronal mass ejection and the largest geomagnetic storm of this solar cycle. The results of this study suggest the Hei flare is a chromospheric manifestation of the X-ray coronal loop structures associated with flares.Visitor, National Solar Observatory, operated by the Association of Universities for Research in Astronomy, Inc., under contract with the National Science Foundation.     

Conjoint analysis of small‐boat recreational fishers in New Zealand

Conjoint analysis is a useful technique to assist recreational managers formulate policy, and develop strategies to efficiently and effectively distribute resources. Accurate estimates of the value of natural resources remain challenging, despite the development of a number of decision analysis techniques. This recreation geography study uses conjoint analysis to examine the relative importance of attributes associated with small‐boat recreational fishing experiences and demonstrates the value of conjoint analysis as a non‐market valuation tool. We found that the choices associated with companionship are the most important factors of recreational fishing and more tangible attributes such as the quality of launch facilities and catch probability are the least important factors.     

Changes in seasonality and timing of peak streamflow in snow and semi‐arid climates of the north‐central United States, 1910–2012

Changes in the seasonality and timing of annual peak streamflow in the north‐central USA are likely because of changes in precipitation and temperature regimes. A source of long‐term information about flood events across the study area is the U.S. Geological Survey peak streamflow database. However, one challenge of answering climate‐related questions with this dataset is that even in snowmelt‐dominated areas, it is a mixed population of snowmelt/spring rain generated peaks and summer/fall rain generated peaks. Therefore, a process was developed to divide the annual peaks into two populations, or seasons, snowmelt/spring, and summer/fall. The two series were then tested for the hypotheses that because of changes in precipitation regimes, the odds of summer/fall peaks have increased and, because of temperature changes, snowmelt/spring peaks happen earlier. Over climatologically and geographically similar regions in the north‐central USA, logistic regression was used to model the odds of getting a summer/fall peak. When controlling for antecedent wet and dry conditions and geographical differences, the odds of summer/fall peaks occurring have increased across the study area. With respect to timing within the seasons, trend analysis showed that in northern portions of the study region, snowmelt/spring peaks are occurring earlier. The timing of snowmelt/spring peaks in three regions in the northern part of the study area is earlier by 8.7– 14.3 days. These changes have implications for water interests, such as potential changes in lead‐time for flood forecasting or changes in the operation of flood‐control dams. Copyright © 2015 John Wiley & Sons, Ltd.     

The shape, topography, and geology of Tempel 1 from Deep Impact observations

Deep Impact images of the nucleus of Comet Tempel 1 reveal pervasive layering, possible impact craters, flows with smooth upper surfaces, and erosional stripping of material. There are at least 3 layers 50-200 m thick that appear to extend deep into the nucleus, and several layers 1-20 m thick that parallel the surface and are being eroded laterally. Circular depressions show geographical variation in their forms and suggest differences in erosion rates or style over scales >1 km. The stratigraphic arrangement of these features suggests that the comet experienced substantial periods of little erosion. Smooth surfaces trending downslope suggest some form of eruption of materials from this highly porous object. The Deep Impact images show that the nucleus of Tempel 1 cannot be modeled simply as either an onion-layer or rubble pile structure.     

Climate change and hydrology at the prairie margin: Historic and prospective future flows of Canada's Red Deer and other Rocky Mountain rivers

The South Saskatchewan River Basin of southern Alberta drains the transboundary central Rocky Mountains region and provides the focus for irrigation agriculture in Canada. Following extensive development, two tributaries, the Oldman and Bow rivers, were closed for further water allocations, whereas the Red Deer River (RDR) remains open. The RDR basin is at the northern limit of the North American Great Plains and may be suitable for agricultural expansion with a warming climate. To consider irrigation development and ecological impacts, it is important to understand the regional hydrologic consequences of climate change. To analyse historic trends that could extend into the future, we developed century‐long discharge records for the RDR, by coordinating data across hydrometric gauges, estimating annual flows from seasonal records, and undertaking flow naturalization to compensate for river regulation. Analyses indicated some coordination with the Pacific decadal oscillation and slight decline in summer and annual flows from 1912 to 2016 (?0.13%/year, Sen's slope). Another forecasting approach involved regional downscaling from the global circulation models, CGCMI‐A, ECHAM4, HadCM3, and NCAR‐CCM3. These projected slight flow decreases from the mountain headwaters versus increases from the foothills and boreal regions, resulting in a slight increase in overall river flows (+0.1%/year). Prior projections from these and other global circulation models ranged from slight decrease to slight increase, and the average projection of ?0.05%/year approached the empirical trend. Assessments of other rivers draining the central and northern Rocky Mountains revealed a geographic transition in flow patterns over the past century. Flows from the rivers in Southern Alberta declined (around ?0.15%/year), in contrast to increasing flows in north‐eastern British Columbia and the Yukon. The RDR watershed approaches this transition, and this study thus revealed regional differentiation in the hydrological consequences from climate change.     

Marine debris collects within the North Pacific Subtropical Convergence Zone

Floating marine debris, particularly derelict fishing gear, is a hazard to fish, marine mammals, turtles, sea birds, coral reefs, and even human activities. To ameliorate the economic and environmental impact of marine debris, we need to efficiently locate and retrieve dangerous debris at sea. Guided by satellite-derived information, we made four flights north of Hawaii in March and April 2005. During these aerial surveys, we observed over 1800 individual pieces of debris, including 122 derelict fishing nets. The largest debris concentrations were found just north of the North Pacific Transition Zone Chlorophyll Front (TZCF) within the North Pacific Subtropical Convergence Zone (STCZ). Debris densities were significantly correlated with sea-surface temperature (SST), chlorophyll-a concentration (Chla), and the gradient of Chla. A Debris Estimated Likelihood Index (DELI) was developed to predict where high concentrations of debris would be most likely in the North Pacific during spring and early summer.     

Developing oxygen isotope proxies from archaeological sources for the study of Late Holocene human–climate interactions in coastal southwest Florida

Oxygen isotopes (δ¹⁸O) derived from archaeological Mercenaria campechiensis shells and Ariopsis felis otoliths potentially provide low-latitude paleoclimate data for studying Late Holocene human–climate interactions in coastal southwest Florida. Specimens analyzed come from the Pineland site complex. Deposits record abrupt and subtle environmental changes appearing to have been climate-related and to have impacted the sedentary human residents. One archaeological shell-otolith set dates to 2nd/3rd century A.D. within the Roman Optimum (RO) climatic episode. A second set dates to 13th/14th century A.D. within the Little Ice Age (LIA). A modern shell-otolith set was analyzed for comparison. δ¹⁸O_ARAGONITE of modern and LIA shells suggest similar seasonal conditions. RO shell is 1‰ more positive during summer, suggesting higher estuarine salinity than in modern and LIA times. Modern and LIA otoliths also have similar δ¹⁸O_ARAGONITE. Estimated Winter temperatures are within measured instrument records. Summer temperatures are overestimated reflecting Summer migration into less-saline water. Estimated Summer temperatures for RO otolith are similar to today's, suggesting elevated estuarine salinity and diminished rainy season, consistent with similar aged zooarchaeological assemblages. Comparisons of two taxa aid in interpreting archaeological δ¹⁸O data; however, early results are mixed with expected profiles for RO specimens and unexpected profiles for LIA specimens.