Anthropogenic Land Use and Land Cover Changes—A Review on Its Environmental Consequences and Climate Change

Journal of the Indian Society of Remote Sensing, Journal Year: 2022, Volume and Issue: 50(8), P. 1615 - 1640

Published: June 7, 2022

Language: Английский

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A meteorological overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign over the southeastern Atlantic during 2016–2018: Part 1 – Climatology

Atmospheric chemistry and physics, Journal Year: 2021, Volume and Issue: 21(22), P. 16689 - 16707

Published: Nov. 16, 2021

Abstract. In 2016–2018, the ObseRvations of Aerosols above CLouds and their intEractionS (ORACLES) project undertook 3-month-long deployments to southeastern (SE) Atlantic Ocean using research aircraft better understand impact biomass burning (BB) aerosol transport SE on climate. this (part 1 meteorological overview) paper, climatological features at monthly timescales are investigated. The southern African easterly jet (AEJ-S), defined as zonal easterlies over 600–700 hPa exceeding 6 m s−1 around 5–15∘ S, is a characteristic feature mid-level circulation Africa that was also during deployment months August 2017, September 2016, October 2018. Climatologically, AEJ-S develops lower altitudes (∼ 3 km; 700 hPa) between 5–10∘ S in August, while it 4 km 600 further south (5–15∘ S) October, largely driven by strong sensible heating plateau. Notable anomalous characteristics months, compared climatology (2000–2018), include following: (1) weaker than mean, with an additional upper-level aloft km) 10∘ S. 2017 drier climatology, stronger Benguela low-level (LLJ) 925–950 along Namibian coast Atlantic. Consistent this, anticyclone closer mean. (2) During intensity similar although heat low vertical motion land slightly climatology. LLJ large-scale were (3) 2018, anticyclone. 2018 wetter coastal region all sea surface temperatures (SST) warmer means, but mean cloud fraction only noticeably reduced 2017. A weak can explain offshore black carbon (BC) mixing ratios within European Centre for Medium-Range Weather Forecasts (ECMWF) Copernicus Atmosphere Monitoring Service (CAMS) reanalysis, BC peak altitude, 2–3 km, below AEJ-S. wave disturbance associated weakening through reduction strength

Language: Английский

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Cloud processing and weeklong ageing affect biomass burning aerosol properties over the south-eastern Atlantic

Communications Earth & Environment, Journal Year: 2022, Volume and Issue: 3(1)

Published: Aug. 18, 2022

Abstract Southern Africa produces a third of global biomass burning emissions, which have long atmospheric lifetime and influence regional radiation balance climate. Here, we use airmass trajectories to link different aircraft observations investigate the evolution biomass-burning aerosols during their westward transport from over south-eastern Atlantic, where semi-permanent stratocumulus cloud deck is located. Our results show secondary organic aerosol formation initial 3 days transport, followed by decreases in via photolysis before reaching equilibrium. Aerosol absorption wavelength dependency with ageing, due an increase particle size photochemical bleaching brown carbon. Cloud processing, including aqueous-phase reaction scavenging, contributes oxidation aerosols, while it strongly reduces large diameter particles single-scattering albedo aerosols. Together, these processes resulted marine boundary layer fewer yet more oxidized absorbing

Language: Английский

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First TanSat CO2 retrieval over land and ocean using both nadir and glint spectroscopy

Remote Sensing of Environment, Journal Year: 2024, Volume and Issue: 304, P. 114053 - 114053

Published: Feb. 19, 2024

Language: Английский

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Cloud adjustments from large-scale smoke–circulation interactions strongly modulate the southeastern Atlantic stratocumulus-to-cumulus transition

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(18), P. 12113 - 12151

Published: Sept. 19, 2022

Abstract. Smoke from southern Africa blankets the southeastern Atlantic Ocean June to October, producing strong and competing aerosol radiative effects. effects on transition between overcast stratocumulus scattered cumulus clouds are investigated along a Lagrangian (air-mass-following) trajectory in regional climate large eddy simulation models. Results compared with observations three recent field campaigns that took place August 2017: ObseRvations of Aerosols above CLouds their intEractionS (ORACLES), Aerosol Radiative Impacts Forcing: Year 2017 (CLARIFY), Layered Interactions Clouds (LASIC). The case study is set up around joint ORACLES–CLARIFY flight near Ascension Island 18 2017. sampled upstream an ORACLES 15 likely entrained into marine boundary layer later during flight. first simulated WRF-CAM5 model distinct setups: (1) FireOn, which smoke emissions any resulting smoke–cloud–radiation interactions included; (2) FireOff, no (3) RadOff, microphysical included but does not interact directly radiation. Over course trajectory, differences free tropospheric thermodynamic properties FireOn FireOff nearly identical those showing aerosol–radiation primarily responsible for These non-intuitive: addition expected heating within core plume, there also “banding” effect cooler temperature (∼1–2 K) greatly enhanced moisture (>2 g kg−1) at plume top. This banding caused by vertical displacement former continental troposphere anomalous diabatic due absorption sunlight manifests as few hundred meters per day reduction large-scale subsidence over ocean. A (LES) then forced fields taken outputs runs. Cases run selectively perturbing one variable (e.g., number concentration, temperature, moisture, velocity) time better understand contributions different indirect (microphysical), “large-scale” semi-direct (above-cloud changes), “local” (below-cloud absorption) Despite more than 5-fold increase cloud droplet concentration when including concentrations, minimal fraction evolution LES comparing base perturbed dynamic forcings. factor 2 decrease background concentrations shifts classical entrainment-driven “deepening–warming” trade precipitation-driven “drizzle-depletion” open cells, however. changes WRF-simulated adjustments strongly influence terms both rate deepening (especially inversion jump subsidence) final effect). Such would have been possible simulate using small-domain alone.

Language: Английский

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Factors affecting precipitation formation and precipitation susceptibility of marine stratocumulus with variable above- and below-cloud aerosol concentrations over the Southeast Atlantic

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(4), P. 2769 - 2793

Published: March 2, 2022

Abstract. Aerosol–cloud–precipitation interactions (ACIs) provide the greatest source of uncertainties in predicting changes Earth's energy budget due to poor representation marine stratocumulus and associated ACIs climate models. Using situ data from 329 cloud profiles across 24 research flights NASA ObseRvations Aerosols above CLouds their intEractionS (ORACLES) field campaign September 2016, August 2017, October 2018, it is shown that contact between above-cloud biomass burning aerosols over Southeast Atlantic Ocean was with precipitation suppression a decrease susceptibility (So) aerosols. The 173 “contact” aerosol concentration (Na) greater than 500 cm−3 within 100 m tops had 50 % lower rate (Rp) 20 So, on average, compared 156 “separated” Na less up at least tops. Contact separated statistically significant differences droplet (Nc) effective radius (Re) (95 confidence intervals two-sample t test are reported). 84 90 higher Nc 1.4 1.6 µm Re profiles. In clean boundary layers (below-cloud 350 cm−3), 25 31 0.2 0.5 Re. polluted exceeding 98 108 1.8 On other hand, insignificant average liquid water path, thickness, meteorological parameters like surface temperature, tropospheric stability, estimated inversion strength. These results suggest microphysical properties were driven by rather effects, adjustments existing relationships Rp model parameterizations should be considered account for role ACIs.

Language: Английский

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Dust-planetary boundary layer interactions amplified by entrainment and advections

Atmospheric Research, Journal Year: 2022, Volume and Issue: 278, P. 106359 - 106359

Published: July 25, 2022

Mineral dust contributes to more than half of the global aerosol loading. However, radiative impacts aerosols on planetary boundary layer (PBL) structure have not been explored sufficiently. During a typical storm event over Tarim Basin, exhibit well-mixed distribution during daytime in spite shallow particles accumulated at higher altitudes. By contrast, nocturnal plumes are located near surface due stable stratification. We demonstrate that these differentiated vertical distributions determine spatial heterogeneity loading, fluxes and PBL height variations. Dust cause suppression nighttime promotion through modulating atmospheric budgets. Specifically, dust-induced cooling effect within directly inhibits development. is then amplified by entrainment processes resulting excessively low height, especially for below but top. weaken updrafts from downdrafts free atmosphere, which further reduce mixing attenuating horizontal advection, eventually amplify suppression. At night, near-surface stimulate warm unstable lower generate advection heating promote Our study highlights importance specifying parameters activities quantifying dust-PBL interactions.

Language: Английский

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A meteorological overview of the ORACLES (ObseRvations of Aerosols above CLouds and their intEractionS) campaign over the southeastern Atlantic during 2016–2018: Part 2 – Daily and synoptic characteristics

Atmospheric chemistry and physics, Journal Year: 2022, Volume and Issue: 22(21), P. 14209 - 14241

Published: Nov. 8, 2022

Abstract. Part 1 (Ryoo et al., 2021) provided a climatological overview of the ObsErvation Aerosols above CLouds and their intEractionS (ORACLES) period assessed representativeness deployment years. In part 2, more detailed meteorological analyses support interpretation airborne measurements for aerosol transport its interaction with low clouds over southeastern (SE) Atlantic Ocean during September 2016, August 2017, October 2018 deployments at daily synoptic scale. The key characteristics 2016 are (1) southern African easterly jet (AEJ-S), centered around 600 hPa (∼4 km), which strengthens throughout month in concert warming continental heat low, strongest winds occurring 23 September. These advect both moisture free troposphere. (2) Mid-tropospheric black carbon (BC) is entrained times into boundary layer, (3) convection land dry south about 10∘ S moist north S. mean low-cloud fraction (low CF) well correlated high tropospheric stability (LTS, r=0.44–0.73 flight domain; 0–10∘ E, 5–25∘ S) moderately layer height (BLH, r=0.37–0.52), defined as altitude maximum vertical gradient moisture. For 2017 deployment, primary that AEJ-S lower (∼3 km; ∼700 hPa) further (5–7∘ than only becomes established by 20 August, separate present aloft 500 (∼5.5 km) before that, mid-tropospheric BC–RH coupling after develops, 3 km, CF less closely LTS (r=0.16–0.57) BLH (r=0.11–0.25) (4) reaches 700 Namibian–Kalahari dryland (∼15–25∘ S, ∼18–24∘ E), generating plume subsequently advected AEJ-S. develops hPa, driven Kalahari (∼10–25∘ ∼12–24∘ but it diminishes time moves southward, offshore advection BC water vapor strongly modulated 8–10∘ early October, this decreases mid-latitude frontal systems develop weakens mid-to-late AEJ-S–low-level (LLJ) coastal Namibian region relationship among all months, largely reduced strong LLJ, especially to cloud deck's south, insignificant compared other 2 partially due variability introduced passage disturbance.

Language: Английский

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More biomass burning aerosol is being advected westward over the southern tropical Atlantic since 2003

The Science of The Total Environment, Journal Year: 2025, Volume and Issue: 965, P. 178506 - 178506

Published: Jan. 30, 2025

Language: Английский

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Aerosols over Africa: sources, properties, and distribution

Elsevier eBooks, Journal Year: 2025, Volume and Issue: unknown, P. 1 - 64

Published: Jan. 1, 2025

Language: Английский

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