scholarly journals Glacier Fluctuations and Climate in the Cordillera Blanca, Peru

1990 ◽  
Vol 14 ◽  
pp. 136-140 ◽  
Author(s):  
Georg Kaser ◽  
Alcides Ames ◽  
Marino Zamora
Keyword(s):  
Seasonal Temperature ◽  
Wet Season ◽  
Equilibrium Line Altitude ◽  
Cordillera Blanca ◽  
Covered Area ◽  
Recession Rates ◽  
Tropical Areas ◽  
Precipitation Records ◽  
The Tropics

With a total of 723 km2 of glaciers (1970) the Cordillera Blanca includes the largest glacier-covered area in the tropics. The climate is characterized by relatively large daily and small seasonal temperature variations as well as by a distinct succession between a dry (May–September) and a wet season (October–April). Since the early 1970s an ablation stake network has been installed on the tongues of the glaciers Uruashraju and Yanamarey. The determination of the equilibrium-line altitude at each end of a wet season was possible, showing a fair correlation with temperature, but not with the precipitation records of the nearby climatological station Querococha. Mean ablation rates at the lowest parts of the glacier tongues are markedly higher during the wet season than during the dry season. Reasons are presumably to be found in the seasonal variation of cloudiness and air moisture rates. Terminus variations of four glaciers in the Cordillera Blanca have been monitored since the early seventies, earlier positions are reconstructed back to 1948 by vertical air photographs. For the glaciers Uruashraju and Yanamarey the terminus positions of 1939 are known from an early map. The general retreat of glaciers in the Cordillera Blanca during the last five decades correlates with the global attitude of glaciers and especially with the attitude of glaciers in other tropical areas. Decreased recession rates with minor advances (1974–79 and 1985–86) are accompanied by lower annual temperatures and preceded and accompanied by years with relatively high annual precipitation sums.

scholarly journals Glacier Fluctuations and Climate in the Cordillera Blanca, Peru

1990 ◽  
Vol 14 ◽  
pp. 136-140 ◽  
Author(s):  
Georg Kaser ◽  
Alcides Ames ◽  
Marino Zamora
Keyword(s):  
Seasonal Temperature ◽  
Wet Season ◽  
Equilibrium Line Altitude ◽  
Cordillera Blanca ◽  
Covered Area ◽  
Recession Rates ◽  
Tropical Areas ◽  
Precipitation Records ◽  
The Tropics

With a total of 723 km2 of glaciers (1970) the Cordillera Blanca includes the largest glacier-covered area in the tropics. The climate is characterized by relatively large daily and small seasonal temperature variations as well as by a distinct succession between a dry (May–September) and a wet season (October–April). Since the early 1970s an ablation stake network has been installed on the tongues of the glaciers Uruashraju and Yanamarey. The determination of the equilibrium-line altitude at each end of a wet season was possible, showing a fair correlation with temperature, but not with the precipitation records of the nearby climatological station Querococha. Mean ablation rates at the lowest parts of the glacier tongues are markedly higher during the wet season than during the dry season. Reasons are presumably to be found in the seasonal variation of cloudiness and air moisture rates. Terminus variations of four glaciers in the Cordillera Blanca have been monitored since the early seventies, earlier positions are reconstructed back to 1948 by vertical air photographs. For the glaciers Uruashraju and Yanamarey the terminus positions of 1939 are known from an early map. The general retreat of glaciers in the Cordillera Blanca during the last five decades correlates with the global attitude of glaciers and especially with the attitude of glaciers in other tropical areas. Decreased recession rates with minor advances (1974–79 and 1985–86) are accompanied by lower annual temperatures and preceded and accompanied by years with relatively high annual precipitation sums.

Road Construction and Rainfall as Landslide Triggers in the Rio Lucma Catchment, Eastern Cordillera Blanca, Peru

2021 ◽  
Author(s):  
Lorena Abad ◽  
Daniel Hölbling ◽  
Adam Emmer
Keyword(s):  
Satellite Imagery ◽  
Southern Oscillation ◽  
Road Construction ◽  
Automated Analysis ◽  
Rainfall Data ◽  
Construction Work ◽  
Visual Interpretation ◽  
Wet Season ◽  
Cordillera Blanca ◽  
The Road

<p>Extensive road construction works were recently undertaken in the remote eastern part of the Peruvian Cordillera Blanca, aiming at better connecting isolated mountain communities with regional administrative centres. In the Río Lucma catchment, approximately 47 km of roads were constructed between 2015 and 2018, triggering several landslides that affected an approximate area of 32 ha. We identified and characterised these landslides by combining field mapping, visual interpretation and semi-automated analysis of satellite imagery (PlanetScope and RapidEye-2), and analysis of rainfall data from two stations of the Servicio Nacional de Meteorología e Hidrología del Perú (SENAMHI). We investigated in detail three specific areas of interest, where we identified, delineated, and described 56 landslides. We classified the landslides in relation to their position to the road as: landslides downslope the roads (48.2%), complex landslides crossing the roads (46.4 %), and landslides onto the road (5.3%). According to the type of movement, we found that the slide-type movement (60.7%) prevails over the flow-type movement (39.3%). Timewise, we found that 75% of landslides were observed on satellite imagery simultaneously with road construction work, while the remaining 25% were identified between one week and seven months after the roads had been constructed. We analysed lagged cumulative rainfall data against the occurrence of these subsequent landslides, determining that a two-week rainfall accumulation can act as triggering factor of landslides after road construction work. In general, 51% of the landslides were observed during the wet season (November to April) while 41.1% occurred during El Niño–Southern Oscillation (ENSO) strong cool phase or “La Niña” period. We observed that the majority of mapped landslides were directly (e.g., landslides resulting from slope undercutting) or indirectly associated with road constructions (e.g., rainfall-induced landslides resulting from a combination of extreme precipitation over slopes with decreased stability) and that the road constructions also may set preconditions for subsequent rainfall-triggered landslides.</p>

scholarly journals Design and Build a Multilevel Mace Nutmeg Dryer to Improve the People's Economy

SinkrOn ◽  
2021 ◽  
Vol 6 (1) ◽  
pp. 107-112
Author(s):  
Ihsan Ihsan ◽  
Dirja Nur Ilham ◽  
Reza Ade Putra ◽  
Rudi Arif Candra ◽  
Arie Budiansyah
Keyword(s):  
Software Design ◽  
Economic Value ◽  
Research Work ◽  
Test Results ◽  
Drying Process ◽  
Wet Season ◽  
Drying Time ◽  
Agricultural Community ◽  
Design Software

Nutmeg is a source of income for some people in South Aceh, and some types of nutmeg, like mace nutmeg, are of better quality. Mace nutmeg is also an agricultural community with great economic value and benefits for humans, as it can be processed into spices and herbs. A range of products includes nutmeg oil and medicines. The harvesting and drying of mace nutmeg, which is still considered a problem by nutmeg growers, cannot be isolated from the processing of the basic ingredients. The natural process of drying mace nutmeg involves the use of sunshine, which necessitates a considerable drying time. Therefore nutmeg farmers frequently complain of erratic weather, especially during the wet season. The constant rain can cause the mace to rot, causing the nutmeg farming community's revenue to become unstable. Methods and steps of research work starting from the study of literature, determination of design specifications, hardware design, software design, toolmaking, tool testing.Good results were reached with the dryness of the mace nutmeg, which can be adjusted, and without putting into account the weather in the drying process, which is usually done with the heat of the sun, per the results of the testing of the designed tools.The average dryness of mace nutmeg is at a temperature of 45 percent with a time of 4 hours and a capacity of 100 grams; according to the test results of the automatic mace drying machine, it produces 50 grams of dry mace.  

Influence of Headwater Reservoirs on Climate Change Impacts and Flood Frequency in the Kabul River Basin

2022 ◽  
Author(s):  
Yar M. Taraky ◽  
Yongbo Liu ◽  
Bahram Gharabaghi ◽  
Edward McBean ◽  
Prasad Daggupati ◽  
...  
Keyword(s):  
Climate Change ◽  
River Basin ◽  
Assessment Tool ◽  
Climate Change Impacts ◽  
Flood Frequency ◽  
Climate Change Scenarios ◽  
Wet Season ◽  
Quarter Century ◽  
Covered Area ◽  
Kabul River

While climate change impacts vary globally, for the Kabul River Basin (KRB), concerns are primarily associated with frequent flooding. This research describes the influence of headwater reservoirs on projections of climate change impacts and flood frequency, and how the riparian countries can benefit from storing of floodwaters for use during dry seasons. Six climate change scenarios and two Representative Concentration Pathways (RCPs) are used in three periods of a quarter-century each. The Soil and Water Assessment Tool (SWAT) is used to assess how the proposed reservoirs will reduce flooding by ~38% during the wet season, reduce the flood frequency from five to 25 years return period, and increase low flows by ~110% during the dry season, which reflect an ~17.5% reduction in the glacier-covered area by the end of the century. The risks and benefits of reservoirs are highlighted in light of the developmental goals of Afghanistan and Pakistan.

General Characteristics and Variability of Climate in the Amazon Basin and its Links to the Global Climate System

2001 ◽  
Author(s):  
Jose A. Marengo ◽  
Carlos A. Nobre
Keyword(s):  
Surface Temperature ◽  
Land Surface ◽  
Large Scale ◽  
Amazon Basin ◽  
Global Climate ◽  
River System ◽  
Climate System ◽  
Wet Season ◽  
Tropospheric Circulation ◽  
The Tropics

The Amazon region is of particular interest because it represents a large source of heat in the tropics and has been shown to have a significant impact on extratropical circulation, and it is Earth’s largest and most intense land-based convective center. During the Southern Hemisphere summer when convection is best developed, the Amazon basin is one of the wettest regions on Earth. Amazonia is of course not isolated from the rest of the world, and a global perspective is needed to understand the nature and causes of climatological anomalies in Amazonia and how they feed back to influence the global climate system. The Amazon River system is the single, largest source of freshwater on Earth. The flow regime of this river system is relatively unimpacted by humans (Vörösmarty et al. 1997 a, b) and is subject to interannual variability in tropical precipitation that ultimately is translated into large variations in downstream hydrographs (Marengo et al. 1998a, Vörösmarty et al. 1996, Richey et al. 1989a, b). The recycling of local evaporation and precipitation by the forest accounts for a sizable portion of the regional water budget (Nobre et al. 1991, Eltahir 1996), and as large areas of the basin are subject to active deforestation there is grave concern about how such land surface disruptions may affect the water cycle in the tropics (see reviews in Lean et al. 1996). Previous studies have emphasized either how large-scale atmospheric circulation or land surface conditions can directly control the seasonal changes in rainfall producing mechanisms. Studies invoking controls of convection and rainfall by large-scale circulation emphasize the relationship between the establishment of upper-tropospheric circulation over Bolivia and moisture transport from the Atlantic ocean for initiation of the wet season and its intensity (see reviews in Marengo et al. 1999). On the other hand, Eltahir and Pal (1996) have shown that Amazon convection is closely related to land surface humidity and temperature, while Fu et al. (1999) indicate that the wet season in the Amazon basin is controlled by both changes in land surface temperature and the sea surface temperature (SST) in the adjacent oceans, depending if the region is north-equatorial or southern Amazonia.

scholarly journals A Statistical Analysis of Some Measures of the State of A Glacier’s “Health”

1972 ◽  
Vol 11 (61) ◽  
pp. 73-79 ◽  
Author(s):  
R. E. Dugdale
Keyword(s):  
Statistical Analysis ◽  
Conceptual Models ◽  
Statistical Tests ◽  
Small Sample ◽  
The State ◽  
Equilibrium Line ◽  
Equilibrium Line Altitude ◽  
Regional Determination

AbstractData from Norwegian glaciers and statistical tests are presented which suggest that vertical net-budget gradient, ablation gradient and equilibrium-line altitude can be taken as characteristic for any particular glacier. The usefulness of these conceptual models as predictive techniques for the regional determination of glacier net budget when only a small sample is available, and in palaeo-net-budget studies, is shown to be limited.

Diet determination of cattle grazing in the Sanyati communal areas in Zimbabwe

2006 ◽  
Vol 34 ◽  
pp. 35-40
Author(s):  
Hanne H. Hansen ◽  
Jørgen Madsen
Keyword(s):  
Plant Species ◽  
Cattle Grazing ◽  
Dry Season ◽  
Particle Identification ◽  
Grass Species ◽  
Wet Season ◽  
Communal Area ◽  
Communal Areas

SummaryThe diet of cattle grazing in the Sanyati communal area, Zimbabwe was determined using plant particle identification from faeces from intact animals, and faeces and oesophageal extrusa from fistulated animals. A total of 130 plant genus, species and types were identified. The twenty most frequently occurring species in the samples comprised between 76 and 90% of the identifiable diet. The most frequent grass species were more than half of the identified diet in the dry season while they were half or less of the identified diet in the wet season. There were more plant species identified in the wet season than in the dry season. Significant differences were found when comparing the plant species identified in faeces to those in oesophageal extrusa from fistulated animals. This may be due to incomplete recovery of ingesta in the bags, or to the loss of identifiable particles in the faeces when compared to oesophageal extrusa because of digestibility. More research is needed to validate the use of oesophageal extrusa for diet botanical determination.

scholarly journals The impact of seasonality on niche breadth, distribution range and species richness: a theoretical exploration of Janzen's hypothesis

2016 ◽  
Vol 283 (1835) ◽  
pp. 20160349 ◽  
Author(s):  
Xia Hua
Keyword(s):  
Temperature Variation ◽  
Empirical Studies ◽  
Tropical Species ◽  
Seasonal Temperature ◽  
Thermal Niche ◽  
Trade Offs ◽  
Seasonal Temperature Variation ◽  
Latitudinal Patterns ◽  
The Tropics ◽  
The Impact

Being invoked as one of the candidate mechanisms for the latitudinal patterns in biodiversity, Janzen's hypothesis states that the limited seasonal temperature variation in the tropics generates greater temperature stratification across elevations, which makes tropical species adapted to narrower ranges of temperatures and have lower effective dispersal across elevations than species in temperate regions. Numerous empirical studies have documented latitudinal patterns in species elevational ranges and thermal niche breadths that are consistent with the hypothesis, but the theoretical underpinnings remain unclear. This study presents the first mathematical model to examine the evolutionary processes that could back up Janzen's hypothesis and assess the effectiveness of limited seasonal temperature variation to promote speciation along elevation in the tropics. Results suggest that trade-offs in thermal tolerances provide a mechanism for Janzen's hypothesis. Limited seasonal temperature variation promotes gradient speciation not due to the reduction in gene flow that is associated with narrow thermal niche, but due to the pleiotropic effects of more stable divergent selection of thermal tolerance on the evolution of reproductive incompatibility. The proposed modelling approach also provides a potential way to test a speciation model against genetic data.

Rainfall erosivity and its estimation for Australia's tropics

Soil Research ◽  
1998 ◽  
Vol 36 (1) ◽  
pp. 143 ◽  
Author(s):  
B. Yu
Keyword(s):  
Model Performance ◽  
Daily Rainfall ◽  
Annual Rainfall ◽  
Rainfall Erosivity ◽  
Wet Season ◽  
R Factor ◽  
Different Seasons ◽  
Monthly Distribution ◽  
The Tropics ◽  
Parameter Values

Pluviograph data at 6-min intervals for 41 sites in the tropics of Australia were used to compute the rainfall and runoff factor (R-factor) for the Revised Universal Soil Loss Equation (RUSLE), and a daily rainfall erosivity model was validated for these tropical sites. Mean annual rainfall varies from about 300 mm at Jervois (015602) to about 4000 at Tully (032042). The corresponding R-factor ranges from 1080 to 33500 MJ·mm/(ha ·h·year). For these tropical sites, both rainfall and rainfall erosivity are highly seasonal with a single peak in February mostly. Summer months (November–April) typically contribute about 80% of annual rainfall and about 90% of the R-factor. The daily erosivity model performed better for the tropical sites with a marked wet season in summer in comparison to model performance in temperate regions of Australia where peak rainfall and peak rainfall erosivity may occur in different seasons. A set of regional parameters depending on seasonal rainfall was developed so that the R-factor and its seasonal distribution can be estimated for sites without pluviograph data. The prediction error using the regional parameter values is about 20% for the R-factor and 1% for its monthly distribution for these tropical sites.

Scats can reveal the presence and habitat use of cryptic rock-dwelling macropods

2006 ◽  
Vol 54 (5) ◽  
pp. 325 ◽  
Author(s):  
Wendy R. Telfer ◽  
Anthony D. Griffiths ◽  
David M. J. S. Bowman
Keyword(s):  
Habitat Use ◽  
Radio Telemetry ◽  
Classification Tree ◽  
Habitat Preferences ◽  
Wet Season ◽  
Survey Tool ◽  
Faecal Pellets ◽  
Tropical Environments ◽  
The Tropics ◽  
Larger Sample

The rock-dwelling macropod species of the tropics of the Northern Territory, Australia, are behaviourally elusive and difficult to observe in their rugged habitats. Hence, little is understood about their ecology. We evaluated the potential of using scats (faecal pellets) as a survey tool for this faunal assemblage by: (1) developing a key to the scats of the species; (2) examining the rates of loss and decomposition of short-eared rock-wallaby (Petrogale brachyotis) scats in these tropical environments; and (3) comparing the distribution of scats of P. brachyotis with the species’ use of space and habitats as determined with radio-telemetry. Classification tree modelling discriminated the scats of the seven macropod species, primarily on the basis of width. The reliability of identification was greatly improved with larger sample sizes and inclusion of a habitat parameter. Rates of scat loss and decay were variable and the greatest losses occurred in the wet season, particularly on sandy soils. Scat censuses underestimated the total area used by P. brachyotis but the distribution of scats showed the same broad pattern of habitat use found by radio-telemetry. We conclude that scats can accurately indicate the presence and habitat preferences of rock-dwelling macropod species.

Sign in / Sign up

Export Citation Format

Share Document