The Importance of the Zagros Mountains Barrier Jet to Future Precipitation in the Fertile Crescent

Evans, Jason P.; Alsamawi, Ali

doi:10.2174/1874282301105010087

Cited by 9 publications

(2 citation statements)

References 32 publications

(45 reference statements)

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“…GCMs do not resolve some important regional details in the current climate of many regions, and may potentially not resolve robust regional features in the climate change signal of those regions (e.g. Schmidli et al 2007;Evans and Alsamawi 2011;Grose et al 2013). Downscaling using a dynamical regional climate model (RCM) or statistical downscaling model may be useful for filling this gap since it offers the prospect of regional-scale detail in the projected climate change signal with a physically plausible basis, or 'added value' .…”

Section: Introductionmentioning

confidence: 99%

Comparison of various climate change projections of eastern Australian rainfall

Grose¹,

Bhend²,

Argüeso³

et al. 2015

AMOJ

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The Australian eastern seaboard is a distinct climate entity from the interior of the continent, with different climatic influences on each side of the Great Dividing Range. Therefore, it is plausible that downscaling of global climate models could reveal meaningful regional detail, or 'added value', in the climate change signal of mean rainfall change in eastern Australia under future scenarios. However, because downscaling is typically done using a limited set of global climate models and downscaling methods, the results from a downscaling study may not represent the range of uncertainty in plausible projected change for a region suggested by the ensemble of host global climate models. A complete and unbiased representation of the plausible changes in the climate is essential in producing climate projections useful for future planning. As part of this aim it is important to quantify any differences in the change signal between global climate models and downscaling, and understand the cause of these differences in terms of plausible added regional detail in the climate change signal, the impact of sub-sampling global climate models and the effect of the downscaling models themselves. Here we examine rainfall projections in eastern Australia under a high emissions scenario by late in the century from ensembles of global climate models, two dynamical downscaling models and one statistical downscaling model. We find no cases where all three downscaling methods show the same clear regional spatial detail in the change signal that is distinct from the host models. However, some downscaled projections suggest that the eastern seaboard could see little change in spring rainfall, in contrast to the substantial rainfall decrease inland. The change signal in the downscaled outputs is broadly similar at the large scale in the various model outputs, with a few notable exceptions. For example, the model median from dynamical downscaling projects a rainfall increase over the entirety of eastern Australia in autumn that is greater than the global models. Also, there are some instances where a downscaling method produces changes outside the range of host models over eastern Australia as a whole, thus expanding the projected range of uncertainty. Results are particularly uncertain for summer, where no two downscaling studies clearly agree. There are also some confounding factors from the model configuration used in downscaling, where the particular zones used for statistical models and the model components used in dynamical models have an influence on results and produce additional uncertainty.

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Section: Introductionmentioning

confidence: 99%

Comparison of various climate change projections of eastern Australian rainfall

Grose¹,

Bhend²,

Argüeso³

et al. 2015

AMOJ

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show abstract

“…This terrain-induced jet, which has a significant impact on precipitation over the region, may be resolved only with high-resolution wind data that can be provided by regional climate models (RCMs). Understanding the ZBJ's behavior is crucial as it provides a dynamical link between water vapor in southern Mesopotamia, which is increasing due to global warming, to precipitation variability in the TEH (Evans 2008;Evans and Alsamawi 2011). This is particularly important during the transition seasons (Evans 2008).…”

Section: Introductionmentioning

confidence: 99%

The Role of Low-Level, Terrain-Induced Jets in Rainfall Variability in Tigris–Euphrates Headwaters

Dezfuli

Zaitchik

Badr

et al. 2017

Journal of Hydrometeorology

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Rainfall variability in the Tigris-Euphrates Headwaters is a result of interaction between topography and meteorological features at a range of spatial scales. Here, we have implemented the Weather Research and Forecasting (WRF) model, driven by NCEP/DOE R2, to better understand these interactions. Simulations were performed over a domain covering most of the Middle-East. The extended simulation period (1983-2013) enables us to study seasonality, interannual variability, spatial variability and extreme events of rainfall. Results showed that the annual cycle of precipitation produced by WRF agrees much more closely with observations than does R2. This was particularly evident during the transition months of April and October, which were further examined to study the underlying physical mechanisms. In both months, WRF improves representation of interannual variability relative to R2, with a substantially larger benefit in April. This improvement results primarily from WRF's ability to resolve two low-level terrain-induced flows in the region that are either absent or weak in NCEP/DOE: one parallel to western edge of the Zagros Mountains, and one along the East Turkish Highlands. The first shows a complete reversal in its direction during wet and dry days: when flowing southeasterly it transports moisture from the Persian Gulf to the region, and when flowing northwesterly it blocks moisture and transports it away from the region. The second is more directly related to synoptic-scale systems and carries moist, warm air from the Mediterranean and Red Seas toward the region. The combined contribution of these flows explains about 50% of interannual variability in both WRF and observations for April and October precipitation.

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Climate change in a region with altitude differences and with precipitation from various sources, South-Central Iran

Naderi

Raeisi

2015

Theor Appl Climatol

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The Importance of the Zagros Mountains Barrier Jet to Future Precipitation in the Fertile Crescent

Cited by 9 publications

References 32 publications

Comparison of various climate change projections of eastern Australian rainfall

Comparison of various climate change projections of eastern Australian rainfall

The Role of Low-Level, Terrain-Induced Jets in Rainfall Variability in Tigris–Euphrates Headwaters

Climate change in a region with altitude differences and with precipitation from various sources, South-Central Iran

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