Forests, atmospheric water and an uncertain future: the new biology of the global water cycle

Forest Ecosystems, Journal Year: 2018, Volume and Issue: 5(1)

Published: March 14, 2018

Theory and evidence indicate that trees other vegetation influence the atmospheric water-cycle in various ways. These influences are more important, complex, poorly characterised than is widely realised. While there little doubt changes tree cover will impact water-cycle, wider consequences remain difficult to predict as underlying relationships processes characterised. Nonetheless, forests vulnerable human activities, these linked aspects of also at risk potential large scale forest loss severe. Here, for non-specialist readers, I review our knowledge links between vegetation-cover climate with a focus on rain (precipitation). highlight advances, uncertainties research opportunities. There significant shortcomings understanding hydrological cycle its representation models. A better role tree-cover reduce some shortcomings. outline illustrate themes where advances may be found. include biology evaporation, aerosols motion, well determine monsoons diurnal precipitation cycles. novel theory—the ‘biotic pump’—suggests evaporation condensation can exert major over dynamics. This theory explains how high rainfall maintained within those continental land-masses sufficiently forested. Feedbacks many result non-linear behaviours dramatic (or gain): example, switching from wet dry local visa-versa). Much remains unknown multiple disciplines needed address this: scientists biologists have play. New ideas, methods data offer opportunities improve understanding. Expect surprises.

Language: Английский

---

Acidity and the multiphase chemistry of atmospheric aqueous particles and clouds

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(17), P. 13483 - 13536

Published: Sept. 10, 2021

Abstract. The acidity of aqueous atmospheric solutions is a key parameter driving both the partitioning semi-volatile acidic and basic trace gases their aqueous-phase chemistry. In addition, phases, e.g., deliquesced aerosol particles, cloud, fog droplets, also dictated by These feedbacks between chemistry have crucial implications for tropospheric lifetime air pollutants, composition, deposition to terrestrial oceanic ecosystems, visibility, climate, human health. Atmospheric research has made substantial progress in understanding multiphase during recent decades. This paper reviews current state knowledge on these with focus cloud systems, which involve inorganic organic Here, we describe impacts phase buffering phenomena. Next, review different regimes chemical reaction mechanisms kinetics, as well uncertainties subsystems incomplete information. Finally, discuss highlight need future investigations, particularly respect reducing emissions acid precursors changing world, advancements field laboratory measurements model tools.

Language: Английский

---

Albedo reduction as an important driver for glacier melting in Tibetan Plateau and its surrounding areas

Earth-Science Reviews, Journal Year: 2021, Volume and Issue: 220, P. 103735 - 103735

Published: July 5, 2021

Language: Английский

---

Machine learning reveals climate forcing from aerosols is dominated by increased cloud cover

Nature Geoscience, Journal Year: 2022, Volume and Issue: 15(8), P. 609 - 614

Published: Aug. 1, 2022

Language: Английский

---

Spontaneous dark formation of OH radicals at the interface of aqueous atmospheric droplets

Proceedings of the National Academy of Sciences, Journal Year: 2023, Volume and Issue: 120(15)

Published: April 3, 2023

Hydroxyl radical (OH) is a key oxidant that triggers atmospheric oxidation chemistry in both gas and aqueous phases. The current understanding of its sources mainly based on known bulk (photo)chemical processes, uptake from gaseous OH, or related to interfacial O

Language: Английский

---

Substantial cooling effect from aerosol-induced increase in tropical marine cloud cover

Nature Geoscience, Journal Year: 2024, Volume and Issue: 17(5), P. 404 - 410

Published: April 11, 2024

Abstract With global warming currently standing at approximately +1.2 °C since pre-industrial times, climate change is a pressing issue. Marine cloud brightening one proposed method to tackle through injecting aerosols into marine clouds enhance their reflectivity and thereby planetary albedo. However, because it unclear how influence clouds, especially cover, both projections the effectiveness of remain uncertain. Here we use satellite observations volcanic eruptions in Hawaii quantify aerosol fingerprint on tropical clouds. We observe large enhancement reflected sunlight, mainly due an aerosol-induced increase cover. This observed strong negative forcing suggests that current level driven by weaker net radiative than previously thought, arising from competing effects greenhouse gases aerosols. implies greater sensitivity Earth’s therefore larger response rising gas concentrations reductions atmospheric air quality measures. our findings also indicate mitigation via plausible most effective humid stable conditions tropics where solar radiation strong.

Language: Английский

---

Lightning declines over shipping lanes following regulation of fuel sulfur emissions

Atmospheric chemistry and physics, Journal Year: 2025, Volume and Issue: 25(5), P. 2937 - 2946

Published: March 11, 2025

Abstract. Aerosol interactions with clouds represent a significant uncertainty in our understanding of the Earth system. Deep convective may respond to aerosol perturbations several ways that have proven difficult elucidate observations. Here, we leverage two busiest maritime shipping lanes world, which emit particles and their precursors into an otherwise relatively clean tropical marine boundary layer, make headway on influence deep clouds. The recent 7-fold change allowable fuel sulfur by International Maritime Organization allows us test sensitivity lightning changes ship plume number-size distributions. We find that, across range atmospheric thermodynamic conditions, previously documented enhancement over has fallen 40 %. is therefore at least partially aerosol-mediated, conclusion supported observations droplet number cloud base, show similar decline lane. These results fundamental implications for aerosol–cloud interactions, suggesting are impacted distribution remote environment.

Language: Английский

---

Aerosol indirect effect from turbulence-induced broadening of cloud-droplet size distributions

Proceedings of the National Academy of Sciences, Journal Year: 2016, Volume and Issue: 113(50), P. 14243 - 14248

Published: Nov. 28, 2016

Significance Atmospheric aerosol concentration is linked to cloud brightness and lifetime through the modulation of precipitation. Generally speaking, larger droplets wider-droplet size distributions form precipitation more efficiently. We create steady-state clouds in laboratory a balance constant injection cloud-droplet removal due settling. As decreased, mean diameter increases, as expected, but also width distribution increases sharply. Theory, simulations, measurements point greater supersaturation variability cause this broadening what can be considered low aerosol/slow microphysics limit.

Language: Английский

---

Evaluation of MODIS Collection 6 aerosol retrieval algorithms over Indo-Gangetic Plain: Implications of aerosols types and mass loading

Remote Sensing of Environment, Journal Year: 2017, Volume and Issue: 201, P. 297 - 313

Published: Sept. 25, 2017

Language: Английский

---

Long-term cloud condensation nuclei number concentration, particle number size distribution and chemical composition measurements at regionally representative observatories

Atmospheric chemistry and physics, Journal Year: 2018, Volume and Issue: 18(4), P. 2853 - 2881

Published: Feb. 28, 2018

Abstract. Aerosol–cloud interactions (ACI) constitute the single largest uncertainty in anthropogenic radiative forcing. To reduce uncertainties and gain more confidence simulation of ACI, models need to be evaluated against observations, particular measurements cloud condensation nuclei (CCN). Here we present a data set – ready used for model validation long-term observations CCN number concentrations, particle size distributions chemical composition from 12 sites on 3 continents. Studied environments include coastal background, rural alpine sites, remote forests an urban surrounding. Expectedly, characteristics are highly variable across site categories. However, they also vary within them, most strongly background group, where concentrations can by up factor 30 one season. In terms activation behaviour, continental stations exhibit very similar ratios (relative particles > 20 nm) range 0.1 1.0 % supersaturation. At transition being inactive becoming active occurs over wider supersaturation spectrum. Several show strong seasonal cycles distributions, e.g. at Barrow (Arctic haze spring), (stronger influence polluted boundary layer air masses summer), rain forest (wet dry season) or Finokalia (wildfire autumn). The relatively little variability throughout year, while short-term high especially site. average hygroscopicity parameter, κ, calculated submicron was highest Mace Head (0.6) lowest station ATTO (0.2–0.3). We performed closure studies based κ–Köhler theory predict concentrations. ratio predicted measured is between 0.87 1.4 five different types κ. temporal well captured, with Pearson correlation coefficients exceeding 0.87. Information many locations important better characterise ACI their But comprehensive aerosol characterisations labour intensive costly. Hence, recommend operating “migrating-CCNCs” conduct collocated concentration distribution individual year least derive seasonally resolved parameter. This way, only continued information greater spatial coverage achieved.

Language: Английский

---