scholarly journals The impact of mineral dust on the day-to-day variability of stratiform cloud glaciation occurrence

2018 ◽  
Author(s):  
Diego Villanueva ◽  
Bernd Heinold ◽  
Patric Seifert ◽  
Hartwig Deneke ◽  
Martin Radenz ◽  
...  
Keyword(s):  
Mineral Dust ◽  
High Latitudes ◽  
Night Time ◽  
Aerosol Model ◽  
Mixing Ratios ◽  
Ice Cloud ◽  
Stratiform Clouds ◽  
Thermodynamic Phase ◽  
The Impact ◽  
Equal Temperature

Abstract. Two different A-Train satellite cloud phase products were analysed together with an aerosol model reanalysis to assess the global day-to-day variability of cloud thermodynamic phase. This variability was analysed for different mixing-ratios of fine and coarse mineral dust during the period 2007–2010 and within a temperature range from +3 °C to −42 °C. Night‑time stratiform clouds were analysed, including stratocumulus, altocumulus, altostratus and cirrus clouds. This analysis showed that the phase of stratiform clouds is highly dependent on temperature and latitude. However, at equal temperature the average occurrence of fully glaciated stratiform clouds was found to increase for higher dust mixing-ratios on a day-to-day basis at mid- and high latitudes. At −15 °C, the increment of ice cloud occurrence between the lowest and highest mixing-ratio was found to be higher for fine dust (+10 % to +18 % occurrence) than for coarse dust (+5 % to +10 %). Surprisingly, the increments were higher in remote regions (e.g. southern high latitudes) where the average dust-mixing ratios are low.

scholarly journals The day-to-day co-variability between mineral dust and cloud glaciation: A proxy for heterogeneous freezing

2019 ◽  
Author(s):  
Diego Villanueva ◽  
Bernd Heinold ◽  
Patric Seifert ◽  
Hartwig Deneke ◽  
Martin Radenz ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Mineral Dust ◽  
Average Frequency ◽  
Static Stability ◽  
Night Time ◽  
Aerosol Model ◽  
Mixing Ratios ◽  
Cloud Ice ◽  
Thermodynamic Phase

Abstract. To estimate the global co-variability between mineral dust aerosol and cloud glaciation, an aerosol model reanalysis was combined with satellite retrievals of cloud thermodynamic phase. We used the CALIPSO-GOCCP and DARDAR products from the A-Train satellite constellation to obtain the cloud phase and the MACC reanalysis to estimate the dust mixing-ratio in the atmosphere. Night-time retrievals within a temperature range from +3 °C to −42 °C for the period 2007–2010 were included. The results confirm that the cloud thermodynamic phase is highly dependent on temperature and latitude. However, at mid- and high latitudes, at equal temperature and within narrow constrains for humidity and static stability the average frequency of fully glaciated clouds increase by +5 to +10 % for higher mineral dust mixing-ratios. The differentiation between humidity-stability regimes reduced the confounding influence of meteorology on the observed relationship between dust and cloud ice. Furthermore, for similar mixing-ratios of mineral dust the cloud ice occurrence-frequency in the Northern Hemisphere was found to be higher than in the Southern Hemisphere at −30 °C but lower at −15 °C. This may suggest a difference in the susceptibility of cloud glaciation to the presence of dust. Based on previous studies, the differences at −15 °C could be explained by higher feldspar fractions in the Southern Hemisphere, while the differences at −30 °C may be explained by the higher freezing efficiency of clay minerals in the Northern Hemisphere.

scholarly journals The day-to-day co-variability between mineral dust and cloud glaciation: a proxy for heterogeneous freezing

2020 ◽  
Vol 20 (4) ◽  
pp. 2177-2199 ◽  
Author(s):  
Diego Villanueva ◽  
Bernd Heinold ◽  
Patric Seifert ◽  
Hartwig Deneke ◽  
Martin Radenz ◽  
...  
Keyword(s):  
Southern Hemisphere ◽  
Northern Hemisphere ◽  
Mineral Dust ◽  
Average Frequency ◽  
Static Stability ◽  
Night Time ◽  
Aerosol Model ◽  
Mixing Ratios ◽  
Cloud Ice ◽  
Thermodynamic Phase

Abstract. To estimate the global co-variability between mineral dust aerosol and cloud glaciation, we combined an aerosol model reanalysis with satellite retrievals of cloud thermodynamic phase. We used the CALIPSO-GOCCP product from the A-Train satellite constellation to assess whether clouds are composed of liquid or ice and the MACC reanalysis to estimate the dust mixing ratio in the atmosphere. Night-time retrievals within a temperature range from +3 to −42 ∘C for the period 2007–2010 were included. The results confirm that the cloud thermodynamic phase is highly dependent on temperature and latitude. However, at middle and high latitudes, at equal temperature and within narrow constraints for humidity and static stability, the average frequency of fully glaciated clouds increases by +5 to +10 % for higher mineral dust mixing ratios. The discrimination between humidity and stability regimes reduced the confounding influence of meteorology on the observed relationship between dust and cloud ice. Furthermore, for days with similar mixing ratios of mineral dust, the cloud ice occurrence frequency in the Northern Hemisphere was found to be higher than in the Southern Hemisphere at −30 ∘C but lower at −15 ∘C. This contrast may suggest a difference in the susceptibility of cloud glaciation to the presence of dust. Based on previous studies, the differences at −15 ∘C could be explained by higher feldspar fractions in the Southern Hemisphere, while the higher freezing efficiency of clay minerals in the Northern Hemisphere may explain the differences at −30 ∘C.

Constraining ice nuclei freezing efficiency using cloud phase observations together with climate models.

2021 ◽  
Author(s):  
Diego Villanueva
Keyword(s):  
Black Carbon ◽  
Climate Models ◽  
Climate Model ◽  
Mineral Dust ◽  
Dust Aerosol ◽  
Strong Constraint ◽  
Aerosol Model ◽  
Aerosol Cloud Interactions ◽  
Thermodynamic Phase ◽  
The Impact

<p>Aerosol-cloud interactions are an important source of uncertainty in current climate models. In particular, the role of mineral dust and soot particles in cloud glaciation is poorly understood. This lack of understanding leads to high uncertainty in climate predictions.</p><p>To estimate the global co-variability between mineral dust aerosol and cloud glaciation, we combined an aerosol model reanalysis with satellite retrievals of cloud thermodynamic phase. Our results confirmed that the cloud thermodynamic phase increases with higher mineral dust concentrations.</p><p>To better understand and quantify the impact of ice-nucleating particles on cloud glaciation, it is crucial to have a reliable estimation of the hemispheric and seasonal contrast in cloud top phase, which is believed to result from the higher dust aerosol loading in boreal spring. For this reason, we locate and quantify these contrasts by combining three different A-Train cloud-phase products for the period 2007-2010. These products rely on a spaceborne lidar, a lidar-radar synergy, and a radiometer-polarimeter synergy. We used these observations to constrain the droplet freezing in the ECHAM-HAM climate model. After tuning, the model leads to more realistic cloud-top-phase contrasts and a dust-driven glaciation effect of 0.14 ± 0.13 Wm−2 between 30–60°N. Our results show that using observations of cloud-top phase contrasts provide a strong constraint for ice formation in mixed-phase clouds and a weak constraint for the associated impact on radiation and precipitation.</p><p>Besides mineral dust, it has been under debate whether black carbon also contributes to cloud glaciation. Therefore, we studied the cloud top phase retrieved by CALIOP during the Australian wildfires in 2020. After repeating the tuning strategy for black carbon, we were able to replicate the increase in ice cloud frequency observed during the wildfires.</p>

scholarly journals Methane emissions from boreal and tropical forest ecosystems derived from in-situ measurements

2007 ◽  
Vol 7 (5) ◽  
pp. 14011-14039 ◽  
Author(s):  
V. Sinha ◽  
J. Williams ◽  
P. J. Crutzen ◽  
J. Lelieveld
Keyword(s):  
Boreal Forest ◽  
Tropical Forest ◽  
Tropical Forests ◽  
Forest Ecosystem ◽  
Boreal Forests ◽  
Forest Ecosystems ◽  
Global Budget ◽  
Night Time ◽  
Mixing Ratios ◽  
The Impact

Abstract. Methane is a climatologically important greenhouse gas, which plays a key role in regulating water vapour in the stratosphere and hydroxyl radicals in the troposphere. Recent findings that vegetation emits methane have stimulated efforts to ascertain the impact of this source on the global budget. In this work, we present the results of high frequency (ca. 1 min−1) methane measurements conducted in the boreal forests of Finland and the tropical forests of Suriname, in April–May, 2005 and October 2005 respectively. The measurements were performed using a gas chromatograph – flame ionization detector (GC-FID). The average of the median mixing ratios during a typical diel cycle were 1.83 μmol mol−1 and 1.74 μmol mol−1 for the boreal forest ecosystem and tropical forest ecosystem respectively, with remarkable similarity in the time series of both the boreal and tropical diel profiles. Night time methane emission flux of the boreal forest ecosystem, calculated from the increase of methane during the night and measured nocturnal boundary layer heights yields a flux of (3.62±0.87)×1011 molecules cm−2 s−1(or 45.5±11 Tg CH4 yr−1 for global boreal forest area). This is a source contribution of circa 8% of the global methane budget. These results highlight the importance of the boreal and tropical forest ecosystems for the global budget of methane. The results are also discussed in the context of recent work reporting high methane mixing ratios over tropical forests using space borne near infra-red spectroscopy measurements.

scholarly journals The impact of solar radiation on polar mesospheric ice particle formation

2018 ◽  
Author(s):  
Mario Nachbar ◽  
Henrike Wilms ◽  
Denis Duft ◽  
Tasha Aylett ◽  
Kensei Kitajima ◽  
...  
Keyword(s):  
Aerosol Particles ◽  
Cloud Formation ◽  
Cold Temperatures ◽  
Polar Mesospheric Clouds ◽  
Mixing Ratios ◽  
Ice Cloud ◽  
Ice Particles ◽  
Small Aerosol ◽  
Mesospheric Clouds ◽  
The Impact

Abstract. Mean temperatures in the polar summer mesopause can drop to 130 K. The cold temperatures in combination with water vapor mixing ratios of a few parts per million give rise to the formation of ice particles. These ice particles may be observed as polar mesospheric clouds. Mesospheric ice cloud formation is believed to initiate heterogeneously on small aerosol particles (r 

scholarly journals Modelling the partitioning of ammonium nitrate in the convective boundary layer

2011 ◽  
Vol 11 (10) ◽  
pp. 28273-28317
Author(s):  
J. M. J. Aan de Brugh ◽  
J. S. Henzing ◽  
M. Schaap ◽  
W. T. Morgan ◽  
H. Coe ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Ammonium Nitrate ◽  
Vertical Mixing ◽  
Phase Fraction ◽  
Aerosol Size Distribution ◽  
Night Time ◽  
Convective Boundary ◽  
Aerosol Model ◽  
The Impact

Abstract. An explanatory model study is presented on semi-volatile secondary inorganic aerosols on three clear days in May 2008 during the IMPACT campaign at the Cabauw tower in the Netherlands. A single column model in combination with the equilibrium aerosol model ISORROPIA is used. This model uses surface observations from IMPACT and calculates the gas-aerosol partitioning of ammonium nitrate. The calculated gas-aerosol equilibrium overestimates the gas phase fraction during daytime, and overestimates the aerosol phase fraction during night-time. This discrepancy can partly be solved when the approach of the gas-aerosol equilibrium is forced to proceed with a delay timescale of up to two hours. Although it is shown that the delay itself has a small effect, the most important effect is caused by the mixing of air from higher altitudes at which the equilibrium is shifted to the aerosol phase. Thus, vertical mixing is shown to have a significant influence on the calculated partitioning at the surface. In some occasions, the correspondence to the observed partitioning improves dramatically. Even though gas-aerosol partitioning of ammonium nitrate is not instantaneous, observations show that a different equilibrium in the upper boundary layer causes aerosol ammonium nitrate concentrations to increase with altitude. Our model calculates similar vertical gradients depending on the assumed speed of gas-aerosol equilibrium. The calculated optical properties of the aerosol show a similar behaviour. The aerosol optical properties depend on the aerosol size distribution both directly, because light scattering depends on particle size, and indirectly, because the equilibration timescale depends on the aerosol sizes. Future studies should therefore focus on a fully size-resolved treatment of the gas-aerosol partitioning. Finally, coarser-resolution models may treat the gas-aerosol equilibrium of ammonium nitrate by calculating the equilibrium with a temperature and humidity sampled at a different altitude. We found that the equilibrium at an altitude of 200 m (night) up to 600 m (day) is representative for the partitioning of ammonium nitrate at the surface in the beginning of May 2008.

scholarly journals Modelling the partitioning of ammonium nitrate in the convective boundary layer

2012 ◽  
Vol 12 (6) ◽  
pp. 3005-3023 ◽  
Author(s):  
J. M. J. Aan de Brugh ◽  
J. S. Henzing ◽  
M. Schaap ◽  
W. T. Morgan ◽  
C. C. van Heerwaarden ◽  
...  
Keyword(s):  
Boundary Layer ◽  
Optical Properties ◽  
Ammonium Nitrate ◽  
Vertical Mixing ◽  
Phase Fraction ◽  
Aerosol Size Distribution ◽  
Night Time ◽  
Convective Boundary ◽  
Aerosol Model ◽  
The Impact

Abstract. An explanatory model study is presented on semi-volatile secondary inorganic aerosols on three clear days in May 2008 during the IMPACT campaign at the Cabauw tower in the Netherlands. A single column model in combination with the equilibrium aerosol model ISORROPIA is used. This model uses surface observations from IMPACT and calculates the gas-aerosol partitioning of ammonium nitrate. The calculated gas-aerosol equilibrium overestimates the gas phase fraction during daytime, and overestimates the aerosol phase fraction during night-time. This discrepancy can partly be solved when the approach of the gas-aerosol equilibrium is forced to proceed with a delay timescale of up to two hours. Although it is shown that the delay itself has a small effect, the most important effect is caused by the mixing of air from higher altitudes at which the equilibrium is shifted to the aerosol phase. Thus, vertical mixing is shown to have a significant influence on the calculated partitioning at the surface. On some occasions, the correspondence to the observed partitioning improves dramatically. Even though gas-aerosol partitioning of ammonium nitrate is not instantaneous, observations show that a different equilibrium in the upper boundary layer causes aerosol ammonium nitrate concentrations to increase with altitude. Our model calculates similar vertical gradients depending on the assumed speed of gas-aerosol equilibrium. The calculated optical properties of the aerosol show a similar behaviour. The aerosol optical properties depend on the aerosol size distribution both directly, because light scattering depends on particle size, and indirectly, because the equilibration timescale depends on the aerosol sizes. Future studies should therefore focus on a fully size-resolved treatment of the gas-aerosol partitioning. Finally, coarser-resolution models may treat the gas-aerosol equilibrium of ammonium nitrate by calculating the equilibrium with a temperature and humidity sampled at a different altitude. We found that the equilibrium at an altitude of 200 m (night) up to 600 m (day) is representative for the partitioning of ammonium nitrate at the surface in the beginning of May 2008.

scholarly journals N<sub>2</sub>O<sub>5</sub> uptake onto saline mineral dust: a potential missing source of tropospheric ClNO<sub>2</sub> in inland China

2021 ◽  
Author(s):  
Haichao Wang ◽  
Chao Peng ◽  
Xuan Wang ◽  
Shengrong Lou ◽  
Keding Lu ◽  
...  
Keyword(s):  
Laboratory Experiments ◽  
Transport Model ◽  
Mineral Dust ◽  
Heterogeneous Reaction ◽  
Chemical Transport Model ◽  
Mixing Ratios ◽  
Nitryl Chloride ◽  
Mass Fractions ◽  
The Impact ◽  
Cl Atoms

Abstract. Nitryl chloride (ClNO2), an important precursor of Cl atoms, significantly affects atmospheric oxidation capacity and O3 formation. However, sources of ClNO2 in inland China have not been fully elucidated. In this work, laboratory experiments were conducted to investigate heterogeneous reaction of N2O5 with eight saline mineral dust samples collected from different regions in China, and substantial formation of ClNO2 was observed. ClNO2 yields, φ(ClNO2), showed large variations (ranging from < 0.05 to ~0.77) for different saline mineral dust samples, largely depending on mass fractions of particulate chloride. In addition, for different saline mineral dust samples, φ(ClNO2) could increase, decrease or show insignificant change as RH increased from 18 % to 75 %. We further found that current parameterizations significantly overestimated φ(ClNO2) for heterogeneous uptake of N2O5 onto saline mineral dust. Assuming a uniform φ(ClNO2) value of 0.10 for N2O5 uptake onto mineral dust, we used a 3-D chemical transport model to assess the impact of this reaction on tropospheric ClNO2 in China, and found that weekly mean nighttime maximum ClNO2 mixing ratios could be increased by up to 85 pptv during a severe dust event in May 2017. Overall, our work showed that heterogeneous reaction of N2O5 with saline mineral dust could be an important source of tropospheric ClNO2 in inland China.

scholarly journals The Impact of Ambient Atmospheric Mineral-Dust Particles on the Calcification of Lungs

Minerals ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 125
Author(s):  
Mariola Jabłońska ◽  
Janusz Janeczek ◽  
Beata Smieja-Król
Keyword(s):  
Mineral Dust ◽  
Smoking Habit ◽  
Lower Lobe ◽  
Ambient Air ◽  
Dust Particles ◽  
Masking Effect ◽  
Amorphous Calcium Carbonate ◽  
Calcium Salts ◽  
The Impact ◽  
First Time

For the first time, it is shown that inhaled ambient air-dust particles settled in the human lower respiratory tract induce lung calcification. Chemical and mineral compositions of pulmonary calcium precipitates in the lung right lower-lobe (RLL) tissues of 12 individuals who lived in the Upper Silesia conurbation in Poland and who had died from causes not related to a lung disorder were determined by transmission and scanning electron microscopy. Whereas calcium salts in lungs are usually reported as phosphates, calcium salts precipitated in the studied RLL tissue were almost exclusively carbonates, specifically Mg-calcite and calcite. These constituted 37% of the 1652 mineral particles examined. Mg-calcite predominated in the submicrometer size range, with a MgCO3 content up to 50 mol %. Magnesium plays a significant role in lung mineralization, a fact so far overlooked. The calcium phosphate (hydroxyapatite) content in the studied RLL tissue was negligible. The predominance of carbonates is explained by the increased CO2 fugacity in the RLL. Carbonates enveloped inhaled mineral-dust particles, including uranium-bearing oxides, quartz, aluminosilicates, and metal sulfides. Three possible pathways for the carbonates precipitation on the dust particles are postulated: (1) precipitation of amorphous calcium carbonate (ACC), followed by its transformation to calcite; (2) precipitation of Mg-ACC, followed by its transformation to Mg-calcite; (3) precipitation of Mg-free ACC, causing a localized relative enrichment in Mg ions and subsequent heterogeneous nucleation and crystal growth of Mg-calcite. The actual number of inhaled dust particles may be significantly greater than was observed because of the masking effect of the carbonate coatings. There is no simple correlation between smoking habit and lung calcification.

scholarly journals Prevalence of nocturia among community-dwelling adults: a population-based study in Malaysia

BMC Urology ◽  
2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Hui-Yin Yow ◽  
John Jeh Lung Tiong ◽  
Chun-Wai Mai ◽  
Esther van der Werf ◽  
Zulkifli Md Zainuddin ◽  
...  
Keyword(s):  
Medical Condition ◽  
Population Based ◽  
Community Dwelling ◽  
Medical Attention ◽  
Night Time ◽  
Cross Sectional ◽  
Population Based Study ◽  
Waking Up ◽  
The Impact

Abstract Background Nocturia is widely prevalent condition with detrimental effects on quality of life and general health. In Malaysia, there is a lack of up-to-date prevalence study on nocturia. This study aimed to investigate the prevalence of nocturia and awareness pertaining to nocturia among Malaysian adults. Methods A cross-sectional population-based study was conducted among Malaysian adults aged ≥ 18 years old. The data was collected by mixed mode self-administered questionnaire from May 2019 to September 2019. Nocturia was defined as one or more voids at night. Results There were a total of 4616 respondents with 74.5% of response rate. The overall prevalence of nocturia among Malaysian adults was found to be 57.3%. In multivariate analysis, respondents aged 31–40 (1.91 [1.52–2.40]) or > 60 years old (2.03 [1.48–2.71]), and those who presented with hypertension (2.84 [2.28–3.53]), diabetes mellitus (1.78 [1.42–2.25]), renal disease (3.58 [1.93–6.63]) or overactive bladder (1.61 [1.10–2.35]) were associated with higher prevalence of nocturia. A significantly lower disease prevalence (p < 0.05) was noted among those aged 41–50 (0.73 [0.59–0.91]), male (0.78 [0.69–0.88]) and Chinese (0.47 [0.30–0.74]) or Indian (0.34 [0.21–0.54]) ethnicities. A total of 37.3% of respondents with nocturia reported that they faced sleeping difficulty about half the time or more after waking up in the middle of night. Those who had ≥ 2 voids per night experienced significantly higher mean bother score than those who had 1 void per night (p < 0.001). Approximately half (56.7%) of all respondents were not aware that night time urination is a medical condition. Only 25.2% of respondents with nocturia had sought medical attention for their nocturia. Conclusions The prevalence of nocturia among Malaysian adults is high and strongly influenced by age, sex, race and comorbidities. However, the general awareness pertaining to nocturia being a health issue remains low among Malaysians. The findings also highlighted the impact of nocturia on sleep and the need for nocturia education to better address this disease.

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