scholarly journals Relationship of lightning flashes frequency with statistical characteristics of convective activity in the atmopshere

2019 ◽  
Vol 485 (1) ◽  
pp. 76-82
Author(s):  
A. V. Eliseev ◽  
A. N. Ploskov ◽  
А. V. Chernokulsky ◽  
I. I. Mokhov

A modification of the commonly used Price-Rind scheme for lightning flashes frequency (LFF), which can be used for calculations with large spatial and time steps, is developed. With such steps, the exponent in the relationship of LFF on convective cloud heights appears to be smaller by a factor of two over land and by one fourth over ocean in comparison to that in the original Price-Rind scheme. The modified version is implemented into the IAP RAS climate model (CM). The results of the lightning flash frequency simulations with the modified scheme agree better with the satellite data than those with the original one. In the IAP RAS CM, global warming (cooling) leads to LFF increase (decrease) in all seasons. The sensitivity of lightning flashes frequency to the surface air temperature change at the global level is estimated equal to 10%/K.

2019 ◽  
Vol 485 (1) ◽  
pp. 273-278 ◽  
Author(s):  
A. V. Eliseev ◽  
A. N. Ploskov ◽  
A. V. Chernokulsky ◽  
I. I. Mokhov

2020 ◽  
Vol 21 (4) ◽  
pp. 671-689 ◽  
Author(s):  
Korbinian Breinl ◽  
Hannes Müller-Thomy ◽  
Günter Blöschl

AbstractWe estimate areal reduction factors (ARFs; the ratio of catchment rainfall and point rainfall) varying in space and time using a fixed-area method for Austria and link them to the dominating rainfall processes in the region. We particularly focus on two subregions in the west and east of the country, where stratiform and convective rainfall processes dominate, respectively. ARFs are estimated using a rainfall dataset of 306 rain gauges with hourly resolution for five durations between 1 h and 1 day. Results indicate that the ARFs decay faster with area in regions of increased convective activity than in regions dominated by stratiform processes. Low ARF values occur where and when lightning activity (as a proxy for convective activity) is high, but some areas with reduced lightning activity exhibit also rather low ARFs as, in summer, convective rainfall can occur in any part of the country. ARFs tend to decrease with increasing return period, possibly because the contribution of convective rainfall is higher. The results of this study are consistent with similar studies in humid climates and provide new insights regarding the relationship of ARFs and dominating rainfall processes.


2021 ◽  
Vol 45 (1) ◽  
Author(s):  
Sumi Na ◽  
Eunyoung Lee ◽  
Hyunjung Kim ◽  
Seiwoong Choi ◽  
Hoonbok Yi

Abstract Background Organism body size is a basic characteristic in ecology; it is related to temperature according to temperature-size rule. Butterflies are affected in various aspects by climate change because they are sensitive to temperature. Therefore, this study was conducted to understand the effect of an increase in temperature due to global warming on the wing of butterflies. Results A total of 671 butterflies belonging to 9 species were collected from 1990 to 2016 in Seoul (336 specimens) and Mokpo (335 specimens). Consequently, as the mean temperature increased, the wing length of the species increased. However, there are exceptions that the Parnassius stubbendorfii, Pieridae canidia, and Pieris rapae wing length of Seoul increased, but the butterfly wing length of Mokpo decreased. Conclusions The positive correlations between the butterfly wing length and mean temperature showed that the change of mean temperature for about 26 years affects the wing length of butterfly species. The exception is deemed to have been influenced by the limited research environment, and further studies are needed. We would expect that it can be provided as basic data for studying effect of climate change.


2020 ◽  
Author(s):  
Ashok K. Luhar ◽  
Ian E. Galbally ◽  
Matthew T. Woodhouse ◽  
Nathan Luke Abraham

Abstract. Although lightning-generated oxides of nitrogen (LNOx) account for only approximately 10 % of the global NOx source, it has a disproportionately large impact on tropospheric photochemistry due to the conducive conditions in the tropical upper troposphere where lightning is mostly discharged. In most global composition models, lightning flash rates used to calculate LNOx are expressed in terms of convective cloud-top height via the Price and Rind (1992) (PR92) parameterisations for land and ocean. We conduct a critical assessment of flash-rate parameterisations that are based on cloud-top height and validate them within the ACCESS-UKCA global chemistry-climate model using the LIS/OTD satellite data. While the PR92 parameterisation for land yields satisfactory predictions, the oceanic parameterisation underestimates the observed flash-rate density severely, yielding a global average of 0.33 flashes/s compared to the observed 9.16 flashes/s over the ocean and leading to LNOx being underestimated proportionally. We formulate new/alternative flash-rate parameterisations following Boccippio’s (2002) scaling relationships between thunderstorm electrical generator power and storm geometry coupled with available data. While the new parameterisation for land performs very similar to the corresponding PR92 one as would be expected, the new oceanic parameterisation simulates the flash-rate observations more accurately, giving a global average of 8.84 flashes/s. The use of the improved flash-rate parameterisations in ACCESS-UKCA changes the modelled tropospheric composition—global LNOx increases from 4.8 to 6.6 Tg N/yr; the ozone (O3) burden increases by 8.5 %; there is an increase in the mid- to upper-tropospheric NOx by as much as 40 ppt; a 13 % increase in the global hydroxyl (OH); a decrease in the methane lifetime by 6.7 %; and a decrease in the lower tropospheric carbon monoxide (CO) by 3–7 %. Overall, the modelled tropospheric NOx and ozone are improved compared to observations, particularly in the Southern Hemisphere and over the ocean.


2020 ◽  
Vol 12 (1) ◽  
pp. 49
Author(s):  
Daud Irundu ◽  
Mir A Beddu ◽  
Najmawati Najmawati

Global warming is one of the major environmental issues of this century. Carbon dioxide (CO2) emissions are the main cause of global warming. Green open space (RTH) such as urban parks, urban forests and green lines play an important role in mitigating global warming and climate change in urban areas because it is able to reduce CO2 from the atmosphere. This study aims to determine the potential of biomass and carbon stored in the Green Open Green Space of Polewali, West Sulawesi. Data collection for stored biomass and carbon is carried out at three green space locations including; Urban forest and city park and green lane each made three plots measuring 20 m x 20 m, and three plots on the Green Line measuring 1200 m. Retrieval of data by measuring tree height and diameter, analysis to obtain the dry volume, biomass and carbon stored for each tree species contained in the Polewali green space. Biomass is obtained by the formula M = BJ x Vk x BEF, the stored carbon value is obtained from the product of biomass by 0.47. The magnitude of the relationship of volume with biomass and carbon uses a regression equation (Ŷ=a+bX). The results show there are types of Glodokan (Polyalthia longifolia), Johar (Senna siamea), Mahogany (Swetenia sp) and Trambesi (Samanea saman) which are spread in the Polewali open green space. Trambesi is a type that has dominant biomass and stored carbon of 381.95 (tons / ha) and 179.52 (ton/ha). Green lane is the type of green space that has the most stored carbon and is currently 440.94 (ton/ha) and 207.24 (ton/ha). The overall green space biomass is 571.83 (ton/ha) and stored carbon is 268.76 (ton/ha) found in urban forests, urban gardens and green belt. The relationship of volume with biomass and stored carbon shows a very strong relationship with the coefficient of determination (R2) of 0.96.  


Author(s):  
Rowan Sutton ◽  
Emma Suckling ◽  
Ed Hawkins

The subject of climate feedbacks focuses attention on global mean surface air temperature (GMST) as the key metric of climate change. But what does knowledge of past and future GMST tell us about the climate of specific regions? In the context of the ongoing UNFCCC process, this is an important question for policy-makers as well as for scientists. The answer depends on many factors, including the mechanisms causing changes, the timescale of the changes, and the variables and regions of interest. This paper provides a review and analysis of the relationship between changes in GMST and changes in local climate, first in observational records and then in a range of climate model simulations, which are used to interpret the observations. The focus is on decadal timescales, which are of particular interest in relation to recent and near-future anthropogenic climate change. It is shown that GMST primarily provides information about forced responses, but that understanding and quantifying internal variability is essential to projecting climate and climate impacts on regional-to-local scales. The relationship between local forced responses and GMST is often linear but may be nonlinear, and can be greatly complicated by competition between different forcing factors. Climate projections are limited not only by uncertainties in the signal of climate change but also by uncertainties in the characteristics of real-world internal variability. Finally, it is shown that the relationship between GMST and local climate provides a simple approach to climate change detection, and a useful guide to attribution studies.


2010 ◽  
Vol 25 ◽  
pp. 161-166 ◽  
Author(s):  
C. Oikonomou ◽  
H. A. Flocas ◽  
G. Katavoutas ◽  
M. Hatzaki ◽  
D. N. Asimakopoulos ◽  
...  

Abstract. The objective of this study is to investigate the relationship of orography over Greece with prolonged dry spells, as represented by the maximum number consecutive dry days (CDD index) during an extremely dry summer. For this purpose a simulation experiment was conducted with the aid of the regional climate model RegCM3.1 using a spatial resolution of 10 km. It was shown that a significant precipitation regime formed over the mountainous areas of continental Greece and Crete during this dry summer, due to orographically forced precipitation, consequently influencing the length of dry spells. Furthermore, the CDD appears spatial variations over the maritime areas, despite the zero or insignificant precipitation. The sensitivity test that was performed with the elimination of orography demonstrated the important role that orography plays in the distribution of CDD, since significant lengthening of extreme dry spells was found over the mountainous areas.


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