Amplification of Australian Heatwaves via Local Land‐Atmosphere Coupling

Hirsch, Annette L.; Evans, Jason P.; Virgilio, Giovanni Di; Perkins‐Kirkpatrick, Sarah E.; Argüeso, Daniel; Pitman, Andrew J.; Carouge, C.; Kala, Jatin; Andrys, Julia; Petrelli, Paola; Rockel, Burkhardt

doi:10.1029/2019jd030665

Cited by 63 publications

(56 citation statements)

References 77 publications

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“…I A is higher in magnitude for SWWA as compared to SEA, and also higher over a larger area in SWWA as compared to SEA, which explains the stronger response. This is consistent with previous work examining land-atmosphere coupling strength over Australia which has also identified SWWA as a hot-spot and weaker coupling over SEA (Hirsch et al, 2019a(Hirsch et al, , 2015b(Hirsch et al, , 2014.…”

Section: Cooling Mechanismsupporting

confidence: 92%

“…Positive I A values imply that changes in HFX drive changes in TMAX and denote a "land-driven" regime, whereas negative values denote an "atmosphere-driven" regime. Following Hirsch et al (2019a), I A values are normalized by subtracting the spatial mean and dividing by the spatial standard deviation for ease of interpretation, and values greater than 0.2 denote strong land-atmosphere coupling. Figs.…”

Section: Discussionmentioning

confidence: 99%

“…We use the Weather Research and Forecasting (WRF) (Skamarock et al, 2019) version 4.0.2, a state-of-the-art and widely used regional atmospheric modelling system. The WRF model has been extensively used and evaluated for multi-decadal regional climate model simulations over Australia (Andrys et al, 2015;Di Virgilio et al, 2019;Evans and McCabe, 2010;Firth et al, 2017;Kala et al, 2020), as well as the simulation of extreme heat events (Hirsch et al, 2019a;Kala et al, 2015b). The model was configured with three nested domains as illustrated in Fig.…”

Section: Model Description and Experimentsmentioning

confidence: 99%

“…The second ensemble differs from the first by using the Mellor-Yamada-Janjic PBL scheme with ETA scheme for the surface layer (Janjić, 1994), and the third ensemble differs from the first ensemble by using the Betts-Miller-Janjic scheme for convection (Betts and Miller, 1986). We do not carry out additional model evaluation against observations in this paper, as all these WRF configurations, which all use the Noah land surface model, have already been extensively evaluated over both SEA and SWWA by numerous studies against maximum and minimum temperature and precipitation observations, and shown to reproduce the observed climatology reasonably well (Andrys et al, 2016(Andrys et al, , 2015Di Virgilio et al, 2019;Evans et al, 2012;Evans and McCabe, 2010;Firth et al, 2017;Hirsch et al, 2019aHirsch et al, , 2019cKala et al, 2015a).…”

Section: Model Description and Experimentsmentioning

confidence: 99%

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Could crop albedo modification reduce regional warming over Australia?

Kala¹,

Hirsch²

2020

Preprint

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Climate observations and projections for Australia show an increase in warm temperature extremes, including the frequency, duration and intensity of heatwaves. Recent global scale studies have suggested that agricultural land-use management options, such as increasing crop albedo, could reducing local warming. Australia has approximately 3,727,210 km2 of cropland agricultural land-use, the majority of which is in southwest Western Australia and southeast Australia. This presents a potential opportunity to reduce regional warming via crop albedo enhancement. We use a regional climate model at 10 km resolution, to show that crop albedo enhancement of up to 0.1 could reduce monthly mean daily maximum temperatures by -1.0&#176;C to -1.2&#176;C, and monthly highest maximum temperatures by up to -1.4&#176;C to -1.6&#176;C during the cropping season. This cooling is approximately 3 times higher over Australia than global climate models predict. We highlight stronger cooling over southwest Western Australia as compared to southeast Australia, the opposite to global model studies which poorly resolve southwestern agricultural regions. The regional cooling was driven by a reduction in surface net shortwave radiation leading to a decrease in both sensible and latent heat flux of up to 50 W m-2 and 20 W m-2 respectively, when albedo is increased by up to 0.1. There were no cloud feedbacks or effects on precipitation. Our results highlight the importance of using regional climate models at a sufficiently high spatial resolution when investigating agricultural land-use management to reduce regional warming.

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Section: Cooling Mechanismsupporting

confidence: 92%

Section: Discussionmentioning

confidence: 99%

Section: Model Description and Experimentsmentioning

confidence: 99%

Section: Model Description and Experimentsmentioning

confidence: 99%

See 2 more Smart Citations

Could crop albedo modification reduce regional warming over Australia?

Kala¹,

Hirsch²

2020

Preprint

Self Cite

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“…Andrys et al (2015) showed that the WRF model was able to adequately simulate the climate of SWA, and these simulations have also been used to assess the impacts of current and future climate on temperature and precipitation (Andrys et al, 2016(Andrys et al, , 2017 as well as climate indices relevant to viticulture for SWA (Firth et al, 2017). The WRF simulations of Andrys et al (2015) have also been benchmarked against other regional climate model simulations across the Australian continent and shown to perform well in simulating both temperature and precipitation (Di Virgilio et al, 2019) as well as heat-wave events (Hirsch et al, 2019). For the years before 1981 the weather conditions measured at the nearby Halls Head weather station (4.2 km away from the Mandurah station) were used.…”

Section: Climate Change Context and Simulation Rationalementioning

confidence: 99%

Climate change overtakes coastal engineering as the dominant driver of hydrologic change in a large shallow lagoon

Huang¹,

Hennig²,

Kala³

et al. 2020

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Abstract. Ecosystems in shallow, micro-tidal lagoons are particularly sensitive to hydrologic changes. Lagoons are also highly complex transitional ecosystems between land and sea, and the signals of direct human disturbance to the lagoon can be confounded by variability of the climate system, but from an effective estuary management perspective the effects of climate versus direct human engineering interventions need to be identified separately. Although many estuarine lagoons have undergone substantial human interventions, such as artificial channels, the effects from the interaction of climate change with engineering interventions have not been well evaluated. This study developed a 3D finite-volume hydrodynamic model to assess changes in hydrodynamics of the Peel-Harvey Estuary, a large chocked-type lagoon, considering how attributes such as water retention time, salinity and stratification have responded to a range of factors, focusing on the drying climate trend and the opening of a large artificial channel over the period from 1970 to 2016, and how they will evolve under current climate projections. The results show that the drying climate has fundamentally changed the hydrology by comparable magnitudes to that of the opening of the artificial channel, and also highlight the complexity of their interacting impacts. Firstly, the artificial channel successfully improved the estuary flushing by reducing average water ages by 20–110 days; while in contrast the reduced precipitation and catchment inflow had a gradual opposite effect on the water ages, and during the wet season this has almost counteracted the reduction brought about by the channel. Secondly, the drying climate caused an increase in the salinity of the lagoon by 10–30 PSU; whilst the artificial channel increased the salinity during the wet season, it has reduced the likelihood of hypersalinity (> 40 PSU) during the dry season in some areas. The impacts also varied spatially in this large lagoon. The southern estuary, which has the least connection with ocean through the natural channel, is the most sensitive to climate change and the opening of the artificial channel. The projected future drying climate is shown to slightly increase the retention time and salinity in the lagoon, and increase the hypersalinity risk in the rivers. The significance of these changes for nutrient retention and estuary ecology are discussed, highlighting the importance of these factors when setting up monitoring programs, environmental flow strategies and nutrient load reduction targets.

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Effect of tropical sub‐seasonal variability on heatwaves over India

Zore

Landu

Gogoi

et al. 2020

Intl Journal of Climatology

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One of the important consequences of changing climate is the increase in temperature extremes and heat stress over many regions of the world. Understanding the various factors that modulate these events on different time scales is of utmost importance due to their great societal relevance. For example, understanding and prediction on sub-seasonal time scales is crucial for reducing losses due to extremes and diligent management of limited resources. In this

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Amplification of Australian Heatwaves via Local Land‐Atmosphere Coupling

Cited by 63 publications

References 77 publications

Could crop albedo modification reduce regional warming over Australia?

Could crop albedo modification reduce regional warming over Australia?

Climate change overtakes coastal engineering as the dominant driver of hydrologic change in a large shallow lagoon

Effect of tropical sub‐seasonal variability on heatwaves over India

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