42 research outputs found
Simplified Equation Models for Greenhouses Gases Assessment in Road Transport Sector in Burkina Faso
Transport sector is cited among the key emitted sector. In Burkina Faso, road transport occupies more than 60% of the emissions of the entire transport sector. However, there is no model equation for greenhouse gases modelling in transport sector. A methodology combining literature review and survey has been adopted to develop the simplified model equation in transport sector. The vehicle type survey allowed the identification of the type of vehicle and the literature review allowed the identification of the key parameters used for greenhouses gases modelling. The results revealed 10 vehicle types for road transport in Burkina Faso such as: Private cars, Public Transport/Buses, Special Vehicle (Ambulances, Fire bus, Funeral vehicles), other vehicle, Motorcycles, Wheeler, Rail, Van, Lorries and Truck Tractor. The keys parameters for greenhouse gases modelling are Fleet availability, Average annual distance travelled, Fuel Economy and Fuel emission factor. For all vehicle type identified simplified model equation was developed to support Burkina Faso, assessing greenhouse gases emission in the sector of transport. This approach could be replicated in other countries in the sub-Saharan Region
Climate change to severely impact West African basin scale irrigation in 2 °C and 1.5 °C global warming scenarios
Abstract West Africa is in general limited to rainfed agriculture. It lacks irrigation opportunities and technologies that are applied in many economically developed nations. A warming climate along with an increasing population and wealth has the potential to further strain the region’s potential to meet future food needs. In this study, we investigate West Africa’s hydrological potential to increase agricultural productivity through the implementation of large-scale water storage and irrigation. A 23-member ensemble of Regional Climate Models is applied to assess changes in hydrologically relevant variables under 2 °C and 1.5 °C global warming scenarios according to the UNFCCC 2015 Conference of Parties (COP 21) agreement. Changes in crop water demand, irrigation water need, water availability and the difference between water availability and irrigation water needs, here referred as basin potential, are presented for ten major river basins covering entire West Africa. Under the 2 °C scenario, crop water demand and irrigation water needs are projected to substantially increase with the largest changes in the Sahel and Gulf of Guinea respectively. At the same time, irrigation potential, which is directly controlled by the climate, is projected to decrease even in regions where water availability increases. This indicates that West African river basins will likely face severe freshwater shortages thus limiting sustainable agriculture. We conclude a general decline in the basin-scale irrigation potential in the event of large-scale irrigation development under 2 °C global warming. Reducing the warming to 1.5 °C decreases these impacts by as much as 50%, suggesting that the region of West Africa clearly benefits from efforts of enhanced mitigation
Sensitivity study of the regional climate model RegCM4 to different convective schemes over West Africa
Abstract. The latest version of RegCM4 with CLM4.5 as a land surface scheme was used to
assess the performance and sensitivity of the simulated West African
climate system to different convection schemes. The sensitivity studies were
performed over the West African domain from November 2002 to December 2004 at
a spatial resolution of 50 km × 50 km and involved five
convective schemes: (i) Emanuel; (ii) Grell; (iii) Emanuel over land and
Grell over ocean (Mix1); (iv) Grell over land and Emanuel over ocean (Mix2);
and (v) Tiedtke. All simulations were forced with ERA-Interim data.
Validation of surface temperature at 2 m and precipitation were conducted
using data from the Climate Research Unit (CRU), Global
Precipitation Climatology Project (GPCP) and the Tropical Rainfall Measurement
Mission (TRMM) during June to September (rainy season), while the simulated
atmospheric dynamic was compared to ERA-Interim data. It is worth noting that
the few previous similar sensitivity studies conducted in the region were
performed using BATS as a land surface scheme and involved less convective
schemes. Compared with the previous version of RegCM, RegCM4-CLM also shows a
general cold bias over West Africa whatever the convective scheme used. This
cold bias is more reduced when using the Emanuel convective scheme. In terms of
precipitation, the dominant feature in model simulations is a dry bias that
is
better reduced when using the Emanuel convective scheme. Considering the good
performance with respect to a quantitative evaluation of the temperature and
precipitation simulations over the entire West African domain and its
subregions, the Emanuel convective scheme is recommended for the study of the
West African climate system
The Regional Climate Change Hyper‐Matrix Framework
Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/95340/1/eost16593.pd
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A tale of two futures: contrasting scenarios of future precipitation for West Africa from an ensemble of regional climate models
The results of a large ensemble of regional climate models lead to two contrasting but plausible scenarios for the precipitation characteristics over West Africa; one where mean precipitation is projected to decrease significantly over the Gulf of Guinea in spring and the Sahel in summer, and the other one where summer precipitation over both regions is projected to increase. Dry and wet models show similar patterns of the dynamic and thermodynamic terms of the moisture budget, although their magnitudes are larger in the dry models. Largest discrepancies are found in the strength of the land-atmosphere coupling, with dry models showing a marked decrease in soil moisture and evapotranspiration. Some changes in precipitation characteristics are consistent for both sets of models. In particular, precipitation frequency is projected to decrease in spring over the Gulf of Guinea and in summer over the Sahel, but precipitation is projected to become more intense
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Changes in the African monsoon region at medium-term time horizon using 12 AR4 coupled models under the A1b emissions scenario
This study documents simulated precipitation and circulation changes through the 20C3M and A1b scenarios. It portrays a robust pattern, associating rainfall deficits in subtropical regions with rainfall excesses over West Africa, except in Northern Senegal and Mauritania, with a significant enhancement of both the April–June rainy season in 10/12 models and of the July–September rainy season in 8/12 models. Eastward to 5 ◦W a northward shift in the latitude of the moisture flux convergence at 850 hPa is evident in 10/11 models (+0.58◦ in mean) and a southward shift in 6/11 models in the western region (−0.24◦) is observed
Robust late twenty-first century shift in the regional monsoons in RegCM-CORDEX simulations
AbstractWe use an unprecedented ensemble of regional climate model (RCM) projections over seven regional CORDEX domains to provide, for the first time, an RCM-based global view of monsoon changes at various levels of increased greenhouse gas (GHG) forcing. All regional simulations are conducted using RegCM4 at a 25 km horizontal grid spacing using lateral and lower boundary forcing from three General Circulation Models (GCMs), which are part of the fifth phase of the Coupled Model Inter-comparison Project (CMIP5). Each simulation covers the period from 1970 through 2100 under two Representative Concentration Pathways (RCP2.6 and RCP8.5). Regional climate simulations exhibit high fidelity in capturing key characteristics of precipitation and atmospheric dynamics across monsoon regions in the historical period. In the future period, regional monsoons exhibit a spatially robust delay in the monsoon onset, an increase in seasonality, and a reduction in the rainy season length at higher levels of radiative forcing. All regions with substantial delays in the monsoon onset exhibit a decrease in pre-monsoon precipitation, indicating a strong connection between pre-monsoon drying and a shift in the monsoon onset. The weakening of latent heat driven atmospheric warming during the pre-monsoon period delays the overturning of atmospheric subsidence in the monsoon regions, which defers their transitioning into deep convective states. Monsoon changes under the RCP2.6 scenario are mostly within the baseline variability
Projected changes in temperature and precipitation over the United States, Central America and the Caribbean in CMIP6 GCMs
The Coupled Model Intercomparison Project Phase 6 (CMIP6) dataset is used to examine projected changes in temperature and precipitation over the United States (U.S.), Central America and the Caribbean. The changes are computed using
an ensemble of 31 models for three future time slices (2021–2040, 2041–2060, and 2080–2099) relative to the reference
period (1995–2014) under three Shared Socioeconomic Pathways (SSPs; SSP1-2.6, SSP2-4.5, and SSP5-8.5). The CMIP6
ensemble reproduces the observed annual cycle and distribution of mean annual temperature and precipitation with biases
between − 0.93 and 1.27 °C and − 37.90 to 58.45%, respectively, for most of the region. However, modeled precipitation is
too large over the western and Midwestern U.S. during winter and spring and over the North American monsoon region in
summer, while too small over southern Central America. Temperature is projected to increase over the entire domain under
all three SSPs, by as much as 6 °C under SSP5-8.5, and with more pronounced increases in the northern latitudes over the
regions that receive snow in the present climate. Annual precipitation projections for the end of the twenty-frst century
have more uncertainty, as expected, and exhibit a meridional dipole-like pattern, with precipitation increasing by 10–30%
over much of the U.S. and decreasing by 10–40% over Central America and the Caribbean, especially over the monsoon
region. Seasonally, precipitation over the eastern and central subregions is projected to increase during winter and spring and
decrease during summer and autumn. Over the monsoon region and Central America, precipitation is projected to decrease
in all seasons except autumn. The analysis was repeated on a subset of 9 models with the best performance in the reference
period; however, no signifcant diference was found, suggesting that model bias is not strongly infuencing the projections.Universidad de Costa Rica/[805-B9-454]/UCR/Costa RicaNational Science Foundation/[AGS-1849654]/NSF/Estados UnidosNational Science Foundation/[AGS-1623912]/NSF/Estados UnidosDepartment of Energy/[2316‐T849‐08]/DOE/Estados UnidosNational Oceanic and Atmospheric Administration/[2316‐T849‐08]/NOAA/Estados UnidosUCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigaciones Geofísicas (CIGEFI)UCR::Vicerrectoría de Investigación::Unidades de Investigación::Ciencias Básicas::Centro de Investigación en Ciencias del Mar y Limnología (CIMAR
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The climatic impact‐driver framework for assessment of risk‐relevant climate information
The climate science and applications communities need a broad and demand-driven concept
to assess physical climate conditions that are relevant for impacts on human and natural systems. Here, we
augment the description of the “climatic impact-driver” (CID) approach adopted in the Working Group I
(WGI) contribution to the Intergovernmental Panel on Climate Change (IPCC) Sixth Assessment Report.
CIDs are broadly defined as “physical climate system conditions (e.g., means, events, and extremes) that
affect an element of society or ecosystems. Depending on system tolerance, CIDs and their changes can be
detrimental, beneficial, neutral, or a mixture of each across interacting system elements and regions.” We give
background information on the IPCC Report process that led to the development of the 7 CID types (heat and
cold, wet and dry, wind, snow and ice, coastal, open ocean, and other) and 33 distinct CID categories, each
of which may be evaluated using a variety of CID indices. This inventory of CIDs was co-developed with
WGII to provide a useful collaboration point between physical climate scientists and impacts/risk experts to
assess the specific climatic phenomena driving sectoral responses and identify relevant CID indices within
each sector. The CID Framework ensures that a comprehensive set of climatic conditions informs adaptation
planning and risk management and may also help prioritize improvements in modeling sectoral dynamics that
depend on climatic conditions. CIDs contribute to climate services by increasing coherence and neutrality
when identifying and communicating relevant findings from physical climate research to risk assessment and
planning activities
Assessment of CMIP6 performance and projected temperature and precipitation changes over South America
We evaluate the performance of a large ensemble of Global Climate Models (GCMs) from the Coupled Model Intercomparison Project Phase 6 (CMIP6) over South America for a recent past reference period and examine their projections of twenty-first century precipitation and temperature changes. The future changes are computed for two time slices (2040–2059 and 2080–2099) relative to the reference period (1995–2014) under four Shared Socioeconomic Pathways (SSPs, SSP1–2.6, SSP2–4.5, SSP3–7.0 and SSP5–8.5). The CMIP6 GCMs successfully capture the main climate characteristics across South America. However, they exhibit varying skill in the spatiotemporal distribution of precipitation and temperature at the sub-regional scale, particularly over high latitudes and altitudes. Future precipitation exhibits a decrease over the east of the northern Andes in tropical South America and the southern Andes in Chile and Amazonia, and an increase over southeastern South America and the northern Andes—a result generally consistent with earlier CMIP (3 and 5) projections. However, most of these changes remain within the range of variability of the reference period. In contrast, temperature increases are robust in terms of magnitude even under the SSP1–2.6. Future changes mostly progress monotonically from the weakest to the strongest forcing scenario, and from the mid-century to late-century projection period. There is an increase in the seasonality of the intra-annual precipitation distribution, as the wetter part of the year contributes relatively more to the annual total. Furthermore, an increasingly heavy-tailed precipitation distribution and a rightward shifted temperature distribution provide strong indications of a more intense hydrological cycle as greenhouse gas emissions increase. The relative distance of an individual GCM from the ensemble mean does not substantially vary across different scenarios. We found no clear systematic linkage between model spread about the mean in the reference period and the magnitude of simulated sub-regional climate change in the future period. Overall, these results could be useful for regional climate change impact assessments across South America