Relationship between topography, tropospheric wind, and frequency of mountain waves in the upper mesosphere over the Kanto area of Japan

Imaging observations of OH airglow were performed at Meiji University, Japan (35.6° N, 139.5° E), from May 2018 to December 2019. Mountainous areas are located to the west of the imager, and westerly winds are dominant in the lower atmosphere throughout the year. Mountain waves (MWs) are generated and occasionally propagate to the upper atmosphere. However, only four likely MW events were identified, which are considerably fewer than expected. There are two possible reasons for the low incidence: (1) MWs do not propagate easily to the upper mesosphere due to background wind conditions, and/or (2) the frequency of MW excitation was low around the observation site. Former possibility is found not to be a main reason to explain the frequency by assuming typical wind profiles in troposphere and upper mesosphere over Japan. Thus, frequency and spatial distribution of orographic wavy clouds were investigated by analyzing images taken by the Himawari-8 geostationary meteorological satellite in 2018. The number of days when wavy clouds were detected in the troposphere around the observation site (Kanto area) was about a quarter of that around the Tohoku area. This result indicates that frequency of over-mountain flow which is thought to be a source of excitation of MWs is low in Kanto area. We also found that the angle between the horizontal wind direction in troposphere and the orientation of the mountain ridge is a good proxy for the occurrence of orographic wavy clouds, i.e., excitation of MWs. We applied this proxy to the topography around the world to investigate regions where MWs are likely to be excited frequently throughout the year to discuss the likelihood of "MW hotspots" at various spatial scale. Graphical Abstract

Effects of point source emission heights in WRF–STILT: a step towards exploiting nocturnal observations in models

An appropriate representation of point source emissions in atmospheric transport models is very challenging. In the Stochastic Time Inverted Lagrangian Transport model (STILT), all point source emissions are typically released from the surface, meaning that the actual emission stack height plus subsequent plume rise is not considered. This can lead to erroneous predictions of trace gas concentrations, especially during nighttime when vertical atmospheric mixing is minimal. In this study we use two WRF–STILT model approaches to simulate fossil fuel CO2 (ffCO2) concentrations: (1) the standard “surface source influence (SSI)” approach, and (2) an alternative “volume source influence (VSI)” approach, where nearby point sources release CO2 according to their effective emission height profiles. The comparison with 14C-based measured ffCO2 data from two-week integrated afternoon and nighttime samples collected at Heidelberg, 30 m above ground level, shows that the root-mean-square deviation (RMSD) between modelled and measured ffCO2 is indeed almost twice as high during night (RMSD = 6.3 ppm) compared to the afternoon (RMSD = 3.7 ppm) when using the standard SSI approach. In contrast, the VSI approach leads to a much better performance at nighttime (RMSD = 3.4 ppm), which is similar to its performance during afternoon (RMSD = 3.7 ppm). Representing nearby point source emissions with the VSI approach could, thus, be a first step towards exploiting nocturnal observations in STILT. To further investigate the differences between these two approaches, we conducted a model experiment in which we simulated the ffCO2 contributions from 12 artificial power plants with typical annual emissions of one million tons of CO2 and with distances between 5 and 200 km from the Heidelberg observation site. We find that such a power plant must be more than 50 km away from the observation site in order for the mean modelled ffCO2 concentration difference between the SSI and VSI approach to fall below 0.1 ppm.

Lost Horizon: Quantifying the Effect of Local Topography on Global 21 cm Cosmology Data Analysis

We present an investigation of the horizon and its effect on global 21 cm observations and analysis. We find that the horizon cannot be ignored when modeling low-frequency observations. Even if the sky and antenna beam are known exactly, forward models cannot fully describe the beam-weighted foreground component without accurate knowledge of the horizon. When fitting data to extract the 21 cm signal, a single time-averaged spectrum or independent multi-spectrum fits may be able to compensate for the bias imposed by the horizon. However, these types of fits lack constraining power on the 21 cm signal, leading to large uncertainties on the signal extraction, in some cases larger in magnitude than the 21 cm signal itself. A significant decrease in uncertainty can be achieved by performing multi-spectrum fits in which the spectra are modeled simultaneously with common parameters. The cost of this greatly increased constraining power, however, is that the time dependence of the horizon’s effect, which is more complex than its spectral dependence, must be precisely modeled to achieve a good fit. To aid in modeling the horizon, we present an algorithm and Python package for calculating the horizon profile from a given observation site using elevation data. We also address several practical concerns such as pixelization error, uncertainty in the horizon profile, and foreground obstructions such as surrounding buildings and vegetation. We demonstrate that our training-set-based analysis pipeline can account for all of these factors to model the horizon well enough to precisely extract the 21 cm signal from simulated observations.

Nocturnal Coleoptera and Hemiptera Diversity at Giam Siak Kecil Bukit Batu Biosphere Reserve Indonesia

Giam Siak Kecil Bukit Batu is a biosphere reserve which one of its functions is as a habitat for wildlife. However, biodiversity data in the Giam Siak Kecil Bukit Batu Biosphere Reserve (GSKBB-BR) is still very minimal, including insects (Coleoptera and Hemiptera). This research was conducted to determine the diversity of Coleoptera and Hemiptera in the GSKBB Biosphere Reserve, Riau, Indonesia. The research was carried out using an exploratory method using "lights trap". The results of the study found 30 species, from 11 families of the order Coleoptera (23 species) and Hemiptera (7 species) in the GSKBB-BR. The diversity index of Coleoptera and Hemiptera at the observation site was moderate (H = 2.73), with a high evenness index (0.80). Scarabaeidae (order Coleoptera) is the family with the highest number of species found (8 species), while the most abundant species were Tibicen linnei and Pomponia fusca (Cicadidae/Hemiptera). Based on their functional roles, Coleoptera and Hemiptera with the highest number are herbivores (17 species), followed by predators (7 species) and decomposers (3 species). The range of values for temperature and humidity at the research site are in normal conditions. The GSKBB-BR area is an important remaining habitat for wildlife in Riau, including various types of insects (Coleoptera and Hemiptera); whose potential still needs to be revealed, and must be managed properly.

Assessment of mangrove condition of Mare Island, North Maluku, Indonesia

This work aimed to determine the condition of mangroves according to the species density and mangrove canopy cover in marine conservation area of Mare Gam Village, Mare Island. The data were collected using the nested quadrat line transect method. The level of species density was calculated based on the criteria for mangrove growth, namely seedlings, saplings and trees. The results showed that there were 9 types of mangroves, based on the value of species density and canopy cover, the condition of mangroves at the observation site was in the good and dense category.

KARAKTERISTIK VEGETASI HABITAT BERSARANG ORANGUTAN (Pongo pygmaeus) di KAWASAN TAMAN NASIONAL SEBANGAU KALIMANTAN TENGAH

This study aims to determine the distribution and characteristics of orangutan nesting habitats and analyze the state of vegetation in orangutan native habitats in the Sebangau National Park, Central Kalimantan. Sampling of research samples was determined by Purposive Sampling on 4 transect lines at the observation site with an area of each transect line of 1000m x 10m, and also made Anvage plots of 20m x 100m in size of 8 lanes. The number of nests found at the research location in the Sebangau National Park Area is 21 nests with an average nest class of 3 and 4. The condition of the forest in the Sebangau National Park area is a type of peat swamp forest located on the banks of the Katingan river, the type of vegetation obtained in the undergrowth is dominated by Malilis, Punak, Tutup Kebali, Sial, Kalalawit because it has the highest INP value (%), while the type vegetation of pole and tree vegetation is dominated by Tatumbu, White Galam, Jambu Burung, Aghatis, Karipak, and Madang Pirawas plants because they have the highest INP value (%). At the research location, it is known to have moderate species diversity because at seedling and sapling vegetation types are known to have moderate species diversity > 2 and at pole and tree vegetation growth rates are known to have moderate diversity levels > 2.Penelitian ini bertujuan untuk menganalisis karakteristik habitat bersarang orangutan serta menganalisis keadaan vegetasi pada habitat bersarang orangutan di kawasan Taman Nasional Sebangau Kalimantan Tengah. Pengambilan data sampel penelitian ditentukan secara Purposive Sampling pada 4 jalur transek di lokasi pengamatan dengan luas masing-masing jalur transek sebesar 1000 m x 10 m, dan juga membuat plot Anveg dengan ukuran 20m x 100 m sebanyak 8 jalur. Jumlah sarang yang ditemukan pada lokasi penelitian di Kawasan Taman Nasional Sebangau adalah sebanyak 21 sarang dengan rata-rata kelas sarang yakni kelas 3 dan 4. Kondisi hutan di kawasan Taman Nasional Sebangau merupakan tipe hutan rawa gambut yang berada di tepi sungai Katingan, jenis vegetasi yang didapat pada tumbuhan bawah didominasi oleh tumbuhan Malilis, Punak, Tutup Kebali, Sial, Kalalawit karena memiliki nilai INP (%) tertinggi, Sedangkan jenis vegetasi tumbuhan tiang dan pohon didominasi oleh jenis tumbuhan Tatumbu, Galam Putih, Jambu Burung, Agathis, Karipak, dan Madang Pirawas karena memiliki nilai INP (%) tertinggi. Pada lokasi penelitian, diketahui memiliki keanekaragaman jenis sedang karena pada jenis vegetasi tingkat semai dan pancang diketahui memiliki keanekaragaman jenis sedang > 2 dan pada jenis vegetasi tingkat pertumbuhan tiang dan pohon diketahui memiliki tingkat keanekaragaman sedang > 2.

Daily Patterns of Foraging and Aggressive Behaviors in Great-tailed Grackle (Quiscalus mexicanus) at an Urban Patch with Availability or Absence of Resources

The Great-tailed Grackle (Quiscalus mexicanus) seems to take advantage of inhospitable environments such as cities. However, it is not yet fully understood how these birds exploit hostile environments to their advantage. Casual observation suggests that this species can obtain resources of biological importance such as food or nesting material from the garbage. As a first approach to the problem, we located a patch outside a residential building in a high-density urban area, where the residents left their trash for pickup. A group of wild Great-tailed grackles was identified as regular visitors. In total, 25 days were recorded at the site (November 2017 - January 2018). Events such as foraging, the number of subjects present at the foraging area, aggressive behaviors between members of the group, and their relation with the presence or absence of the garbage collector truck were registered. The results show a higher number of grackles at the observation site and a higher frequency of foraging behaviors in the presence of garbage collection than in its absence. In its presence, the distribution of foraging during the day follows a normal distribution. In the absence, the distribution shows more variability towards the day. The highest frequency of interactions occurred between two grackles, yet there were records of up to eight subjects. The highest number of aggressions registered took place in the absence of garbage collection than in its presence. Moreover, the focal subject exhibits fewer agonistic behaviors than other group members, a result expected if the producer-scrounger game literature is considered. The outcome is explained in terms of deprivation and availability of resources. Finally, we conclude that grackles can exploit hazardous environments such as cities due to the highly social behaviors exhibited during foraging.