Browsing by Subject "PART I"

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  • Khan, Basit; Banzhaf, Sabine; Chan, Edward C.; Forkel, Renate; Kanani-Suehring, Farah; Ketelsen, Klaus; Kurppa, Mona; Maronga, Bjoern; Mauder, Matthias; Raasch, Siegfried; Russo, Emmanuele; Schaap, Martijn; Suehring, Matthias (2021)
    In this article we describe the implementation of an online-coupled gas-phase chemistry model in the turbulence-resolving PALM model system 6.0 (formerly an abbreviation for Parallelized Large-eddy Simulation Model and now an independent name). The new chemistry model is implemented in the PALM model as part of the PALM-4U (PALM for urban applications) components, which are designed for application of the PALM model in the urban environment (Maronga et al., 2020). The latest version of the Kinetic PreProcessor (KPP, 2.2.3) has been utilized for the numerical integration of gas-phase chemical reactions. A number of tropospheric gas-phase chemistry mechanisms of different complexity have been implemented ranging from the photostationary state (PHSTAT) to mechanisms with a strongly simplified volatile organic compound (VOC) chemistry (e.g. the SMOG mechanism from KPP) and the Carbon Bond Mechanism 4 (CBM4; Gery et al., 1989), which includes a more comprehensive, but still simplified VOC chemistry. Further mechanisms can also be easily added by the user. In this work, we provide a detailed description of the chemistry model, its structure and input requirements along with its various features and limitations. A case study is presented to demonstrate the application of the new chemistry model in the urban environment. The computation domain of the case study comprises part of Berlin, Germany. Emissions are considered using street-type-dependent emission factors from traffic sources. Three chemical mechanisms of varying complexity and one no-reaction (passive) case have been applied, and results are compared with observations from two permanent air quality stations in Berlin that fall within the computation domain. Even though the feedback of the model's aerosol concentrations on meteorology is not yet considered in the current version of the model, the results show the importance of online photochemistry and dispersion of air pollutants in the urban boundary layer for high spatial and temporal resolutions. The simulated NOx and O-3 species show reasonable agreement with observations. The agreement is better during midday and poorest during the evening transition hours and at night. The CBM4 and SMOG mechanisms show better agreement with observations than the steady-state PHSTAT mechanism.
  • Öhman, Hannareeta; Savikko, N. R. N.; Strandberg, T. E.; Kautiainen, H.; Raivio, M. M.; Laakkonen, M. L.; Tilvis, R.; Pitkala, K. H. (2017)
    Background: Neuropsychiatric symptoms (NPS) are common in Alzheimer's disease (AD) and are associated with admission to institutional care. Current guidelines recommend non-pharmacological interventions as the first-line treatment for NPS. However, high-quality randomized studies focused on NPS are scarce. The objective here was to examine whether a regular and long-term exercise programme either at home or as a group-based exercise at an adult day care centre has beneficial effects on AD patients' NPS or permanent institutionalizations. Design, setting, and participants: A randomized, controlled trial with 210 community-dwelling AD patients. Intervention: Two types of intervention comprising (1) group-based exercise in day care centres (GE) and (2) tailored home-based exercise (HE), both twice a week for 12 months, were compared with (3) a control group (CG) receiving usual community care. Measurements: NPS were measured with the Neuropsychiatric Inventory (NPI) at baseline and 6 months, and depression with the Cornell Scale for Depression in Dementia (CSDD) at baseline and 12 months. Data on institutionalizations were retrieved from central registers. Results: No significant differences between the groups were detected in NPI at 6 months or in CSDD at 12 months when analyses were adjusted for age, sex, baseline Clinical Dementia Rating, and Functional Independence Measure. There was no difference in admissions to permanent institutional care between the groups. Conclusions: Regular, long-term exercise intervention did not decrease NPS in patients with AD. (C) 2017 Elsevier Masson SAS and European Union Geriatric Medicine Society. All rights reserved.
  • James, Spencer L.; Lucchesi, Lydia R.; Bisignano, Catherine; Castle, Chris D.; Dingels, Zachary; Fox, Jack T.; Hamilton, Erin B.; Henry, Nathaniel J.; McCracken, Darrah; Roberts, Nicholas L. S.; Sylte, Dillon O.; Ahmadi, Alireza; Ahmed, Muktar Beshir; Alahdab, Fares; Alipour, Vahid; Andualem, Zewudu; Antonio, Carl Abelardo T.; Arabloo, Jalal; Badiye, Ashish D.; Bagherzadeh, Mojtaba; Banstola, Amrit; Baernighausen, Till Winfried; Barzegar, Akbar; Bayati, Mohsen; Bhaumik, Soumyadeep; Bijani, Ali; Bukhman, Gene; Carvalho, Felix; Crowe, Christopher Stephen; Dalal, Koustuv; Daryani, Ahmad; Nasab, Mostafa Dianati; Hoa Thi Do; Huyen Phuc Do; Endries, Aman Yesuf; Fernandes, Eduarda; Filip, Irina; Fischer, Florian; Fukumoto, Takeshi; Gebremedhin, Ketema Bizuwork Bizuwork; Gebremeskel, Gebreamlak Gebremedhn; Gilani, Syed Amir; Haagsma, Juanita A.; Hamidi, Samer; Hostiuc, Sorin; Househ, Mowafa; Igumbor, Ehimario U.; Ilesanmi, Olayinka Stephen; Irvani, Seyed Sina Naghibi; Jayatilleke, Achala Upendra; Kahsay, Amaha; Kapoor, Neeti; Kasaeian, Amir; Khader, Yousef Saleh; Khalil, Ibrahim A.; Khan, Ejaz Ahmad; Khazaee-Pool, Maryam; Kokubo, Yoshihiro; Lopez, Alan D.; Madadin, Mohammed; Majdan, Marek; Maled, Venkatesh; Malekzadeh, Reza; Manafi, Navid; Manafi, Ali; Mangalam, Srikanth; Massenburg, Benjamin Ballard; Meles, Hagazi Gebre; Menezes, Ritesh G.; Meretoja, Tuomo J.; Miazgowski, Bartosz; Miller, Ted R.; Mohammadian-Hafshejani, Abdollah; Mohammadpourhodki, Reza; Morrison, Shane Douglas; Negoi, Ionut; Trang Huyen Nguyen; Son Hoang Nguyen; Cuong Tat Nguyen; Nixon, Molly R.; Olagunju, Andrew T.; Olagunju, Tinuke O.; Padubidri, Jagadish Rao; Polinder, Suzanne; Rabiee, Navid; Rabiee, Mohammad; Radfar, Amir; Rahimi-Movaghar, Vafa; Rawaf, Salman; Rawaf, David Laith; Rezapour, Aziz; Rickard, Jennifer; Roro, Elias Merdassa; Roy, Nobhojit; Safari-Faramani, Roya; Salamati, Payman; Samy, Abdallah M.; Satpathy, Maheswar; Sawhney, Monika; Schwebel, David C.; Senthilkumaran, Subramanian; Sepanlou, Sadaf G.; Shigematsu, Mika; Soheili, Amin; Stokes, Mark A.; Tohidinik, Hamid Reza; Bach Xuan Tran; Valdez, Pascual R.; Wijeratne, Tissa; Yisma, Engida; Zaidi, Zoubida; Zamani, Mohammad; Zhang, Zhi-Jiang; Hay, Simon; Mokdad, Ali H. (2020)
    Background Past research has shown how fires, heat and hot substances are important causes of health loss globally. Detailed estimates of the morbidity and mortality from these injuries could help drive preventative measures and improved access to care. Methods We used the Global Burden of Disease 2017 framework to produce three main results. First, we produced results on incidence, prevalence, years lived with disability, deaths, years of life lost and disability-adjusted life years from 1990 to 2017 for 195 countries and territories. Second, we analysed these results to measure mortality-to-incidence ratios by location. Third, we reported the measures above in terms of the cause of fire, heat and hot substances and the types of bodily injuries that result. Results Globally, there were 8 991 468 (7 481 218 to 10 740 897) new fire, heat and hot substance injuries in 2017 with 120 632 (101 630 to 129 383) deaths. At the global level, the age-standardised mortality caused by fire, heat and hot substances significantly declined from 1990 to 2017, but regionally there was variability in age-standardised incidence with some regions experiencing an increase (eg, Southern Latin America) and others experiencing a significant decrease (eg, High-income North America). Conclusions The incidence and mortality of injuries that result from fire, heat and hot substances affect every region of the world but are most concentrated in middle and lower income areas. More resources should be invested in measuring these injuries as well as in improving infrastructure, advancing safety measures and ensuring access to care.
  • Sinclair, Victoria A.; Moisseev, Dmitri; von Lerber, Annakaisa (2016)
    In this paper it is discussed how dual-polarization radar observations can be used to verify model representations of secondary ice production. An event where enhanced specific differential phase, K-dp, signatures in snow occur at the altitudes where temperatures lie in the range between -8 and -3 degrees C is investigated. By combining radar and surface-based precipitation observations it is shown that these dual-polarization radar signatures are most likely caused by ice with concentrations exceeding those expected from primary ice parameterizations. It is also shown that the newly formed ice particles readily aggregate, which may explain why K-dp values seem to be capped at 0.2-0.3 degrees/km for a Cband radar. For the event of interest, multiple high-resolution (1km) Weather Research and Forecasting (WRF) model simulations are conducted. When the default versions of the Morrison microphysics schemes were used, the simulated number concentration of frozen hydrometeors is much lower than observed and the simulated ice particle concentrations are comparable with values expected from primary ice parameterizations. Higher ice concentrations, which exceed values expected from primary ice parameterizations, were simulated when adhoc thresholds for rain and cloud water mixing ratio in the Hallett-Mossop part of the Morrison scheme were removed. These results suggest that the parameterization of secondary ice production in operational weather prediction models needs to be revisited and that dual-polarization radar observations, in conjunction with ancillary observations, can be used to verify them.
  • Tallavaara, Miikka; Luoto, Miska; Korhonen, Natalia; Järvinen, Heikki; Seppä, Heikki (2015)
    The severe cooling and the expansion of the ice sheets during the Last Glacial Maximum (LGM), 27,000-19,000 y ago (27-19 ky ago) had a major impact on plant and animal populations, including humans. Changes in human population size and range have affected our genetic evolution, and recent modeling efforts have reaffirmed the importance of population dynamics in cultural and linguistic evolution, as well. However, in the absence of historical records, estimating past population levels has remained difficult. Here we show that it is possible to model spatially explicit human population dynamics from the pre-LGM at 30 ky ago through the LGM to the Late Glacial in Europe by using climate envelope modeling tools and modern ethnographic datasets to construct a population calibration model. The simulated range and size of the human population correspond significantly with spatiotemporal patterns in the archaeological data, suggesting that climate was a major driver of population dynamics 30-13 ky ago. The simulated population size declined from about 330,000 people at 30 ky ago to a minimum of 130,000 people at 23 ky ago. The Late Glacial population growth was fastest during Greenland interstadial 1, and by 13 ky ago, therewere almost 410,000 people in Europe. Even during the coldest part of the LGM, the climatically suitable area for human habitation remained unfragmented and covered 36% of Europe.
  • Rannik, U.; Haapanala, S.; Shurpali, Narasinha; Mammarella, I.; Lind, Saara; Hyvönen, Niina; Peltola, O.; Zahniser, Mark; Martikainen, Pertti; Vesala, T. (2015)
    Four gas analysers capable of measuring nitrous oxide (N2O) concentration at a response time necessary for eddy covariance flux measurements were operated from spring until winter 2011 over a field cultivated with reed canary grass (RCG, Phalaris arundinacea, L.), a perennial bioenergy crop in eastern Finland. The instruments were TGA100A (Campbell Scientific Inc.), CW-TILDAS-CS (Aerodyne Research Inc.), N2O / CO-23d (Los Gatos Research Inc.) and QC-TILDAS-76-CS (Aerodyne Research Inc.). The period with high emissions, lasting for about 2 weeks after fertilization in late May, was characterized by an up to 2 orders of magnitude higher emission, whereas during the rest of the campaign the N2O fluxes were small, from 0.01 to 1 nmol m−2 s−1. Two instruments, CW-TILDAS-CS and N2O / CO-23d, determined the N2O exchange with minor systematic difference throughout the campaign, when operated simultaneously. TGA100A produced the cumulatively highest N2O estimates (with 29% higher values during the period when all instruments were operational). QC-TILDAS-76-CS obtained 36% lower fluxes than CW-TILDAS-CS during the first period, including the emission episode, whereas the correspondence with other instruments during the rest of the campaign was good. The reasons for systematic differences were not identified, suggesting further need for detailed evaluation of instrument performance under field conditions with emphasis on stability, calibration and any other factors that can systematically affect the accuracy of flux measurements. The instrument CW-TILDAS-CS was characterized by the lowest noise level (with a standard deviation of around 0.12 ppb at 10 Hz sampling rate) as compared to N2O / CO-23d and QC-TILDAS-76-CS (around 0.50 ppb) and TGA100A (around 2 ppb). We identified that for all instruments except CW-TILDAS-CS the random error due to instrumental noise was an important source of uncertainty at the 30 min averaging level and the total stochastic error was frequently of the same magnitude as the fluxes when N2O exchange was small at the measurement site. Both instruments based on continuous-wave quantum cascade laser, CW-TILDAS-CS and N2O / CO-23d, were able to determine the same sample of low N2O fluxes with a high mutual coefficient of determination at the 30 min averaging level and with minor systematic difference over the observation period of several months. This enables us to conclude that the new-generation instrumentation is capable of measuring small N2O exchange with high precision and accuracy at sites with low fluxes.
  • Moisseev, Dmitri; von Lerber, Annakaisa; Tiira, Jussi (2017)
    Ground-based observations of ice particle size distribution and ensemble mean density are used to quantify the effect of riming on snowfall. The rime mass fraction is derived from these measurements by following the approach that is used in a single ice-phase category microphysical scheme proposed for the use in numerical weather prediction models. One of the characteristics of the proposed scheme is that the prefactor of a power law relation that links mass and size of ice particles is determined by the rime mass fraction, while the exponent does not change. To derive the rime mass fraction, a mass-dimensional relation representative of unrimed snow is also determined. To check the validity of the proposed retrieval method, the derived rime mass fraction is converted to the effective liquid water path that is compared to microwave radiometer observations. Since dual-polarization radar observations are often used to detect riming, the impact of riming on dual-polarization radar variables is studied for differential reflectivity measurements. It is shown that the relation between rime mass fraction and differential reflectivity is ambiguous, other factors such as change in median volume diameter need also be considered. Given the current interest on sensitivity of precipitation to aerosol pollution, which could inhibit riming, the importance of riming for surface snow accumulation is investigated. It is found that riming is responsible for 5% to 40% of snowfall mass. The study is based on data collected at the University of Helsinki field station in Hyytiala during U.S. Department of Energy Biogenic Aerosols Effects on Clouds and Climate (BAECC) field campaign and the winter 2014/2015. In total 22 winter storms were analyzed, and detailed analysis of two events is presented to illustrate the study.
  • Li, Haoran; Tiira, Jussi; von Lerber, Annakaisa; Moisseev, Dmitri (2020)
    In stratiform rainfall, the melting layer (ML) is often visible in radar observations as an enhanced reflectivity band, the so-called bright band. Despite the ongoing debate on the exact microphysical processes taking place in the ML and on how they translate into radar measurements, both model simulations and observations indicate that the radar-measured ML properties are influenced by snow microphysical processes that take place above it. There is still, however, a lack of comprehensive observations to link the two. To advance our knowledge of precipitation formation in ice clouds and provide new insights into radar signatures of snow growth processes, we have investigated this link This study is divided into two parts. Firstly, surface-based snowfall measurements are used to develop a new method for identifying rimed and unrimed snow from X- and Ka-band Doppler radar observations. Secondly, this classification is used in combination with multifrequency and dual-polarization radar observations collected during the Biogenic Aerosols - Effects on Clouds and Climate (BAECC) experiment in 2014 to investigate the impact of precipitation intensity, aggregation, riming and dendritic growth on the ML properties. The results show that the radar-observed ML properties are highly related to the precipitation intensity. The previously reported bright band "sagging" is mainly connected to the increase in precipitation intensity. Ice particle riming plays a secondary role. In moderate to heavy rainfall, riming may cause additional bright band sagging, while in light precipitation the sagging is associated with unrimed snow. The correlation between ML properties and dual-polarization radar signatures in the snow region above appears to be arising through the connection of the radar signatures and ML properties to the precipitation intensity. In addition to advancing our knowledge of the link between ML properties and snow processes, the presented analysis demonstrates how multifrequency Doppler radar observations can be used to get a more detailed view of cloud processes and establish a link to precipitation formation.