Fixed-point Observations Research Articles

Climate change affects plant aboveground biomass by regulating the growth periods in alpine grasslands of the Tibetan Plateau, China

Climate change significantly affects plant biomass and phenological occurrence time in alpine grasslands of Tibetan Plateau. The changes in phenological periods are closely related to the length of vegetative and reproductive growth periods, which may further affect aboveground biomass accumulation. In this study, based on fixed-point observations of plant biomass and phenology as well as the corresponding climatic data from 1997 to 2020 in the alpine grasslands of Tibetan Plateau, we used statistical methods such as ordinary linear regression and piecewise structural equation model to explore the characteristics of interannual climate change in the study area, the variation trends of plant biomass and phenological periods, and the correlations between biomass and phenological and climatic factors. The results showed that mean annual temperature and annual precipitation in the study area increased significantly from 1997 to 2020, suggesting a clear "warm-wet" trend. Aboveground biomass and relative biomass of Stipa sareptana var. krylovii (the dominant species) decreased significantly. However, absolute and relative biomass of subdominant species (Kobresia humilis) increased significantly, indicating that the dominance of K. humilis increased. The warm-wet climates enhanced aboveground biomass accumulation of K. humilis by extending the period of reproductive growth. Mean annual temperature and annual precipitation decreased aboveground biomass of S. sareptana by shortening the length of vegetative growth period. In a word, the warmer and wetter climate significantly affected aboveground biomass accumulation by regulating the changes in the phenological period, and the interspecific difference in their response resulted in a larger change in community composition. This study area may show a trend from alpine grassland to alpine meadow, and thus further works are urgently needed.

Soluble PD-L1 changes in advanced non-small cell lung cancer patients treated with PD-1 inhibitors: an individual patient data meta-analysis.

Currently, first-line immune checkpoint inhibitors (ICIs), including programmed cell death protein-1 (PD-1) inhibitors, are utilized as monotherapy in advanced non-small cell lung cancer (NSCLC) patients with high programmed death ligand-1 (PD-L1) expression (≧50%). Pre-treatment or post-treatment serum soluble PD-L1 (sPD-L1) has been identified as a potential biomarker for assessing ICI efficacy through fixed-point observations. However, existing studies on sPD-L1 changes have produced inconsistent results or have had sample sizes too small to detect clinically meaningful effect sizes. To elucidate the role of sPD-L1, we conducted a collaborative individual patient data meta-analysis of PD-1 inhibitor treatments. We conducted a thorough search of articles in PubMed via Medline, Embase, Scopus, and Cochrane databases from inception to October 20, 2023. Trials were deemed eligible if they contained individual datasets for advanced NSCLC patients, including data on overall survival (OS)/progression-free survival (PFS), as well as pre- and post-treatment sPD-L1 levels after 3-4 cycles of PD-1 inhibitor treatments. Our analysis focused on patients who completed 3-4 cycles of PD-1 inhibitor treatments. The primary outcome measure was OS/PFS, and we assessed changes in sPD-L1 concentration pre- and post-treatment through ELISA analyses. From our search, we identified a potential seven trials, encompassing 256 patients. Among these, two trials with 26 patients met the criteria for inclusion in our primary analyses. Over a median follow-up period of 10 months, pooled univariate analysis revealed that increases in sPD-L1 levels during PD-1 inhibitor treatment were not associated with OS (HR = 1.25; CI: 0.52-3.02)/PFS (HR = 1.42; CI: 0.61-3.30) when compared to cases with sPD-L1 decreases. Subgroup analyses indicated that the impact of sPD-L1 changes on overall mortality/progression-related mortality remained consistent regardless of gender, age, or the type of treatment (nivolumab or pembrolizumab). Our findings suggest that changes in sPD-L1 levels during PD-1 inhibitor treatment do not significantly influence the prognosis of advanced NSCLC patients, regardless of gender, age, or treatment type. Continuous monitoring of sPD-L1 may not offer significant advantages compared to fixed-point observations.

A dataset of fixed-point observations of 10 rare migratory birds in Poyang Lake from 2021 to 2022

A dataset of fixed-point observations of 10 rare migratory birds in Poyang Lake from 2021 to 2022

Analysis of the Variability and Influencing Factors of Ice Thickness during the Ablation Period in Qinghai Lake Using the GPR Ice Monitoring System

As a reliable indicator of regional climate change, the growth and decline of lake ice thickness affect the regional intra–annual heat and energy balance. In this study, a ground-penetrating radar (GPR) ice monitoring system, located approximately 1.7 km west of Bird Island in Qinghai Lake, in the territory of Qinghai Province and located in northwest China, was designed to carry out continuous fixed–point observations of local ice thickness and meteorological elements from 7 to 24 March 2021. The characteristics of continuous daily changes in ice thickness during the ablation period of Qinghai Lake and their relationship with meteorological elements were analyzed. The results showed that the average daily ice thickness of Qinghai Lake increased and then decreased during the observation period, with an average ice thickness of 42.83 cm, an average daily ice thickness range of 39.35~46.15 cm, and a growth rate of 0.54 cm/day during 8–13 March 2021, with an ice melting rate of −0.61 cm/day during 14–24 March 2021. The daily ice thickness variations were divided into two phases, which were relatively stable before dawn and followed a decreasing, increasing, and then decreasing trend during 8–13 March 2021 and a decreasing, increasing (for several hours), and then decreasing trend during 14–24 March 2021. There was a significant positive correlation (R = 0.745, p < 0.01) between near-surface air temperature and ice surface temperature during the observation period, but a significant negative correlation (R = −0.93, p < 0.05) between the average daily ice thickness and cumulative temperature of the ice surface. Temperature was the dominant factor affecting lake ice thickness, as compared to near-surface air humidity, wind speed, and illuminance. However, a sudden increase in wind speed have also played an important role at certain periods. A large number of cracks appeared on the ice surface on 26 March 2021, which, combined with the forces of wind speed, wind direction, and temperature, contributed to the rapid melt of the lake ice. This study filled the gap in situ measurement data on the continuous ice thickness variability during the ablation period in Qinghai Lake. It provided scientific support for the further study of lake ice on the Qinghai–Tibet Plateau (QTP).

Forecasting Alternaria Leaf Spot in Apple with Spatial-Temporal Meteorological and Mobile Internet-Based Disease Survey Data

Early warning of plant diseases and pests is critical to ensuring food safety and production for economic crops. Data sources such as the occurrence, frequency, and infection locations are crucial in forecasting plant diseases and pests. However, at present, acquiring such data relies on fixed-point observations or field experiments run by agricultural institutions. Thus, insufficient data and low rates of regional representative are among the major problems affecting the performance of forecasting models. In recent years, the development of mobile internet technology and conveniently accessible multi-source agricultural information bring new ideas to plant diseases’ and pests’ forecasting. This study proposed a forecasting model of Alternaria Leaf Spot (ALS) disease in apple that is based on mobile internet disease survey data and high resolution spatial-temporal meteorological data. Firstly, a mobile internet-based questionnaire was designed to collect disease survey data efficiently. A specific data clean procedure was proposed to mitigate the noise in the data. Next, a sensitivity analysis was performed on the temperature and humidity data, to identify disease-sensitive meteorological factors as model inputs. Finally, the disease forecasting model of the apple ALS was established using four machine learning algorithms: Logistic regression(LR); Fisher linear discriminant analysis(FLDA); Support vector machine(SVM); and K-Nearest Neighbors (KNN). The KNN algorithm is recommended in this study, which produced an overall accuracy of 88%, and Kappa of 0.53. This paper shows that through mobile internet disease survey and a proper data clean approach, it is possible to collect necessary data for disease forecasting in a short time. With the aid of high resolution spatial-temporal meteorological data and machine learning approaches, it is able to achieve disease forecast at a regional scale, which will facilitate efficient disease prevention practices.

Fixed Point Observations and Characterization of Radioactive Caesium in Tama River

Fixed Point Observations and Characterization of Radioactive Caesium in Tama River

Meteorology and topographic influences on nocturnal ozone increase during the summertime over Shaoguan, China

Ozone (O3) is a typical photochemical product, generally with a maximum value in the late afternoon and a minimum value at night. This study aimed to investigate the variation characteristics of nocturnal O3 in a subtropical urban city (Shaoguan, Guangdong Province, China). The measurement campaigns were conducted from 23 July to July 28, 2020. O3 lidar, aerosol lidar, and wind profile lidar were utilised to detect the vertical distributions of the O3 concentrations, aerosol extinction coefficient, and wind velocity. The topographic features, pollutant data (PM10, PM2.5, O3, SO2, NO2, and CO), and meteorological parameters (temperature, humidity, wind speed, and wind direction) were also analysed. The results showed that the concentration of nocturnal O3 over Shaoguan peaked at midnight. The horizontal wind was dominated by southwest and south winds, and the vertical wind was dominated by downdrafts during the fixed-point observations in Shaoguan. Horizontal transport might have a high impact on the increase in the nocturnal O3 because of high pollutant emissions in upwind cities. This was further justified by the 24-h back trajectories of the air mass generated by the Hybrid Single Particle Lagrangian Integrated Trajectory (HYSPLIT) model. Vertical transport of O3 in the lower or middle troposphere might be induced by the subtropical high and nocturnal mountain-valley breezes. Thus, the vertical mixing of O3 affects the O3 concentration at night.

Population Dynamics of Community Cats Living in a Tourist Area of Onomichi City, Japan, before and after the Trap-Test-Vaccinate-Alter-Return-Monitor Event

ABSTRACT The community cat program (CCP) was recommended by the Ministry of the Environment to reduce cats in local animal shelters and improve stray cat welfare in Japan. It is a non-lethal control measure with stray cats cared for as free-roaming cats for their lifetime in the community, while Trap-Neuter-Return (TNR) or Trap-Test-Vaccinate-Alter-Return-Monitor (TTVARM) activities are carried out. In the CCP, community cat colonies are hypothesized to be closed and static populations. However, it remains unknown whether the cats stay in the colonies, without migration of non-neutered cats following TNR/TTVARM events. We examined the population dynamics of cats before and after a TTVARM event using route censuses (107 days), fixed-point observations, and GPS-tracking in a tourist area in Onomichi. Eleven out of the 30 cats remained in the CCP areas, whereas 13 non-neutered cats immigrated into the CCP areas, within a year, suggesting the CCP program has limited efficacy. Besides, the program cannot support the lifetime management of the cats due rapid turnover of cats. Our results reject the CCP hypothesis, so that the program neither restricts cat breeding nor enhances cat welfare.

A Feasibility Study on a Monitoring for Seagrass beds Using Environmental DNA

In order to protect marine resources listed in the SDGs, it is important to conduct surveys to understand the current status and transition of aquatic species such as fish and seagrass. However, the area and frequency of surveys are often limited due to the lack of manpower and cost. Environmental DNA (eDNA) analysis is a method to obtain information of aquatic species in the sea or rivers. The aquatic species are identified by analyzing DNA contained in the sampled water. The eDNA analysis can be utilized as a new and efficient method for investigating aquatic species. The author is developing a monitoring method for seagrass beds using eDNA. Seagrasses are sessile organisms and don’t move like a fish, the areas where eDNA is generated are fixed. Therefore, eDNA path in a seagrass beds area can be predicted by flow prediction simulation. The monitoring carries out in the path of eDNA released from seagrass. When there is a correlation between the amount of DNA and the amount of biomass, it is possible to gain knowledge of the amount of biomass from sampling water in the path of eDNA. For example, the changes in the amount of biomass due to growth and withering of seagrass beds can be studied by observing the changes in the amount of DNA. The purpose of this study is to examine the feasibility of the monitoring method using experiments, field surveys and numerical simulations for eDNA. The water tank experiments for 15 months, suggested that the amount of seagrass eDNA is related to the seasonal changes in the biomass of seagrass, which has been grown in the water tank. In the conducted four field surveys, the amount of eDNA tended to be high during times of spring with high amounts of seagrasses. In addition, the decomposition process of eDNA were examined by laboratory experiments using sea water. As a result, seagrass DNA contained in the sampling sea water was degraded and undetected within around 5 days. This result suggests that information obtained from the sampling water reflects biological information within a few days. These results suggest the possibility to estimate the changes in biomass by using eDNA in the sea. And, in the field surveys, it was shown that the amount of eDNA is small, so we have recognized that increasing the amount of sampling water and improvement of the DNA analysis method is an issue. This monitoring method is feasible when the collected eDNA is related to a specific seagrass bed. The feasibility of the method was considered using numerical simulation. In the numerical simulation, a particle tracking method using 10 types of simple bay shapes was used to trace the path of eDNA regarded as a particle. When the eDNA started from multiple positions, it was searched for position where the point where DNA starts and arrives is uniquely determined. As a result, at some observation points, the particles that departed from a specific position was observed without being mixed with particles departing from other starting positions, and this was true for all bay types. In addition, the same tendency could be obtained in calculations using the bathymetry of Ago bay, in Mie prefecture. These suggests that it may be possible to monitor seagrass beds by performing fixed-point observations according to the seagrass beds distribution and bay flow. Since few cases in the sea were conducted, the authors intend to continue the survey for the upcoming years and continue the study under various conditions including numerical analysis.

Methane Emissions during the Tide Cycle of a Yangtze Estuary Salt Marsh

Methane (CH4) emissions from estuarine wetlands were proved to be influenced by tide movement and inundation conditions notably in many previous studies. Although there have been several researches focusing on the seasonal or annual CH4 emissions, the short-term CH4 emissions during the tide cycles were rarely studied up to now in this area. In order to investigate the CH4 emission pattern during a tide cycle in Yangtze Estuary salt marshes, frequent fixed-point observations of methane flux were carried out using the in-situ static closed chamber technique. The results indicated that the daily average CH4 fluxes varied from 0.68 mgCH4·m−2·h−1 to 4.22 mgCH4·m−2·h−1 with the average flux reaching 1.78 mgCH4·m−2·h−1 from small tide to spring tide in summer. CH4 fluxes did not show consistent variation with both tide levels and inundation time but increased steadily during almost the whole research period. By Pearson correlation analysis, CH4 fluxes were not correlated with both tide levels (R = −0.014, p = 0.979) and solar radiation (R = 0.024, p = 0.865), but significantly correlated with ambient temperature. It is temperature rather than the tide level mainly controlling CH4 emissions during the tide cycles. Besides, CH4 fluxes also showed no significant correlation with the underground pore-water CH4 concentrations, indicating that plant-mediated transport played a more important role in CH4 fluxes compared with its production and consumption.

Improvements in Perpendicular Reverse Parking by Directing Drivers’ Preliminary Behavior

Driving vehicles requires mastery of a multitude of tasks. Among these, parking is one task that most drivers feel they are not as skilled as they would like to be. In this paper, we focus on improvement of reverse perpendicular parking performance. We began our research by conducting fixed-point observations in a private parking lot to analyze parking behavior in situ. Our analysis indicated that the start position of reversing is the most important aspect of successfully navigating into a target parking space. We then examined the effect of delivering instructions to assist in preliminary vehicle control by giving a target drawn on the road using a head-mounted display-based driving simulator. The results indicated that explicit instructions improve the parking performance for spatial offset, but the effect on the time required for the task could not be clearly confirmed. In summary, directing drivers to alter their preliminary behavior in the perpendicular parking task might be practically useful for improving their performance.

For Colorization using Template Matching Basic Research on

Colorization, also known as colorization, is a term introduced by Wilson Markle in 1970, and is a method of coloring black-and-white images and videos using a computer. Coloring is important. Imagine coloring a picture as an example. The painting before painting only gives information of existence, such as trees, flowers, and clouds. Some things can be identified by color. This does not give us enough information from the picture. But what about coloring? If you paint the sky red, it will be a sunset, and if you paint the ground green, it will be a meadow. In other words, it is possible to express not only the background but also the background. This makes it possible to read information that cannot be understood only in black and white. With the development of digital devices such as smartphones these days, the chances of seeing black-and-white images are decreasing, but in modern times, black-and-white images are used for X-ray images, MRI images, aerial photographs, fixed-point observations, etc. There are many opportunities to be lost. The development of color photography began in the world in the 1800s, and the development of color photography began in Japan in 1940. In other words, the photographs before that were black and white, and colorization was used to colorize them. Currently, many researchers are studying colorization methods and processes, and the processing time and the burden on users are being reduced. However, software that can perform highly complete colorization is expensive, and some are complicated to operate. Therefore, in this research, as basic research for the development of a fully automatic colorization program for free software, color images (template images) lacking information by template matching using ZNCC and black-and-white images with similar brightness patterns are colored. We made a prototype of a colorization program that restores images.

Population ecology of Red-necked Spurfowl Pternistis afer in the coastal towns of the Eastern Cape province, South Africa

Conserved remnants of indigenous vegetation patches and corridors are regarded as important components of the built environment for the survival of birds. Field research was conducted at Boknes and Cannon Rocks in the Eastern Cape Province, South Africa to study habitat use, movement, and dispersal of two Red-necked Spurfowl Pternistis afer subpopulations during 2004–2007. Surveys included trapping, marking, releasing, and censusing spurfowl by traversing the study area on a regular basis, as well as fixed point observations. The density of Red-necked Spurfowl varied from 0.66–1 spurfowl ha−1. The sex ratio for female to male was 1:1.28. The average home range for adult males was 6.3 ha. The results suggest that supplementary feeding does not change the population structure or dispersion, nor does it improve productivity or density. The most determining factor influencing spurfowl populations was the presence of indigenous vegetation patches and continuous corridors of coastal vegetation allowing populational interchange and outright dispersal. Conservation measures are suggested to promote the survival of Red-necked Spurfowl in coastal town biotopes. This includes the removal of free ranging chickens Gallus gallus domesticus, which could harbour contagious disease, reduced use of hazardous substances, such as insecticides and herbicides in gardens, and the conservation of well-positioned green patches and corridors.

Assessing the spatial dispersion of products of the fumarolic activity using remotely sensed snow color in an alpine environment

The sulfur-bearing volcanic gases SO2 and H2S have a direct impact on ecosystems and can endanger human health. Timely information regarding dispersion patterns of fumarolic gases is crucial for predicting potential impacts. However, real-time fixed-point observations are difficult in alpine areas where snow accumulation is seasonably variable, in addition to being potentially dangerous to on-the-ground observers. Thus, in this study we tested a novel technique using a colorimeter, digital camera, and an unmanned aerial vehicle (UAV) imagery to evaluate the dispersion of sulfur particles from fumarolic gas over a snow-covered location in the Tateyama Mountain Range, central Japan, from 2013 to 2015. Snow samples were collected at the depths ranging from 0 to 0.5 cm and the sulfur particle content was determined by X-ray fluorescence analysis. The dissolved ion concentrations in snow melt solutions were analyzed to clarify the contribution of Asian yellow dust (KOSA) to the snow surface color. RGB color images captured by the UAV were converted to CIE-Lab color space with three axes: X axis changed from red to green (a*), Y axis from yellow to blue (b*), and Z axis from white to black (L*). The color levels of green and yellow increased in the snow surface of fumarolic areas and showed a significant correlation with the densities of sulfur particles on the snow surface (r2 = 0.853, P < 0.001). These results indicated that aerial images of snow surface color can be used for estimation of sulfur particle dispersion from fumarolic gases.

Factors contribution to oxygen concentration in Qinghai-Tibetan Plateau

Oxygen (O2) is essential for physiological activity in humans. On the Qinghai-Tibetan Plateau, with an average altitude of more than 4 km, hypoxia can seriously damage local residents health, especially the respiratory system. When an organism cannot fully compensate for insufficient physiological function caused by hypoxia, acute and chronic mountain sickness (AMS and CMS) will occur. Previous studies have suggested that the relative oxygen concentration (ROC) in the near-ground air shows no obvious changes at different altitudes. However, during field work in the Qinghai-Tibetan Plateau, we found that, in addition to altitude, surface vegetation coverage and weather conditions may also have an impact on ROC. The results of data analysis showed that altitude and 500 hPa air temperature (500 hPa-T) were negatively correlated with ROC, while vegetation coverage was directly proportional to ROC. Based on principal component analysis (PCA), the results indicated that altitude, vegetation coverage and 500 hPa-T accounted for 65.5% of the total variance in ROC, of which the variance interpretation rate of vegetation coverage was highest (33.1%), followed by 500 hPa-T (28.5%) and altitude (3.9%). Absolute oxygen concentration (AOC) was calculated using the Ideal-Gas Equation. Using this equation, we found that altitude, vegetation coverage and 500 hPa-T accounted for 78.9% of the total variance in AOC, of which the variance interpretation rate of altitude was highest (45.9%), followed by vegetation coverage (18.5%) and 500 hPa-T (14.5%). AOC was negatively correlated with the incidence of CMS, and elevated AOC significantly reduced the incidence of CMS. The science community should pay more attention to this topic as a further decrease in ROC could significantly increase instability and risk in populations at high altitudes. These findings could enhance our understanding of the relationships between oxygen concentration, altitude, vegetation, weather conditions and their interactions. In addition, this research may not only play an important guiding role in human and animal health in high altitude areas, but also significantly deepen our understanding of the risks in high altitude environments under global warming both theoretically and practically. Multi-source data, including in - situ measurement data, remote sensing data, and model reanalysis data, will facilitate further implementations in this direction. Future work can be carried out using more fixed-point observations and by expanding the spatio-temporal extent of relevant data in high altitudes.

Characteristics of Students Who Frequently Conduct Plant Observations: Toward Fostering Leaders and Supporters of Fixed-Point Observation of Forests

In order to foster leaders and supporters of fixed-point observation for sustainable forest management, it is considered effective to focus on students who have demonstrated potential for fixed-point observations of forests in the universal education stage. This study aims to identify the characteristics of students who frequently conduct plant observations, which is the basis for the fixed-point observation of forests, including methods involving photography. We conducted a questionnaire survey, which consisted of 19 questions that provided insight into junior high school students’ experiences, opportunities, and interests related to plant observation. We compared students who have conducted plant observations with those who have not, using Fisher’s exact test and multiple comparisons using the Benjamini and Hochberg method. The ratio of students who frequently conducted plant observations was significantly higher among female students than male students, and their characteristics differed by gender. The significant characteristics of male students included farm work experience and niche hobbies such as camping and lighting a bonfire, as well as using digital single-lens reflex cameras for photography; female students had relatively niche hobbies such as enjoying science. Students who increased the frequency of plant observations after the lecture about fixed-point observations of forests had an inclination toward social studies and tended not to use a smartphone for photography.

Laser Visualization of the Development of Long Line-Type Mutli-Cell Upsets in Back-Biased SOI SRAMs

An interesting multiple-cell upset (MCU) phenomenon in silicon-on-insulator (SOI) static random access memorys (SRAMs) featuring long lines of more than ten flipped cells is studied. Such an abnormal MCU phenomenon was recently observed for back-biased SOI SRAMs in a heavy-ion test. Using a two-photon absorption-based laser system, we performed fixed-point observations and visualized the development of long line-type MCUs with increasing back bias. The visualization results provided insights to elucidate the mechanism behind these phenomena. Furthermore, using fixed-point observations, we extracted the length of MCUs for various bias conditions and laser strike positions. It was found that for all cases studied, the line length could be explained using an analytical model.

The extent and intensity of the urban heat island in Iași city, Romania

The study underlines the characteristics of the urban heat island of Iași (Iași’s UHI) on the basis of 3 years of air temperature measurements obtained by fixed-point observations. We focus on the identification of UHI development and intensity as it is expressed by the temperature differences between the city centre and the rural surroundings. Annual, seasonal and daily characteristics of Iasi’s UHI are investigated at the level of the classical weather observation. In brief, an intensity of 0.8 °C of UHI and a spatial extension which corresponds to the densely built area of the city were delineated. The Iasi UHI is stronger during summer calm nights—when the inner city is warmer with 2.5–3 °C than the surroundings—and is weaker during windy spring days. The specific features of Iași’s UHI bear a profound connection to the specificity of the urban structure, the high atmospheric stability in the region and the local topography. Also, the effects of Iași’s UHI upon some environmental aspects are presented as study cases. For instance, under the direct influence of UHI, we have observed that in the city centre, the apricot tree blossoms earlier (with up to 4 days) and the depth of the snow cover is significantly lower (with up to 10 cm for a rural snow depth of 30 cm) than in the surrounding areas.

Heat and dry islands observed over Jakarta, Indonesia, in 2012

Abstract. Recent population increases in urban areas of Asian countries have extended artificial land cover, increased energy consumption, and caused various problems. Higher air temperatures over urban areas (heat islands) degrade residential environments and affect human health. In Jakarta, the largest city in Indonesia and the second largest city in Asia, previous studies have relied on only a few observation points and physically-based models. To study the thermal environment in Jakarta in more detail, we performed seven fixed-point temperature and humidity observations from the dry to the pre-monsoon season (from 16 September to 18 October) in 2012. Over densely urbanized areas, higher temperatures and lower humidity were observed around noon compared with the sparsely urbanized areas. The maximum differences in temperature and specific humidity were found to be around 3 °C and 0.005 kg/kg, respectively. The differences in temperature and humidity became smaller in the afternoon because of the penetration of sea breezes. At night, the differences became larger again because the sea breeze weakened. Then, a difference of around 3°C was observed, except in the early morning. Although the difference in daytime temperature was smaller between densely urbanized areas and suburban areas, similar tendency was also confirmed in the daily time series averaged for sunny days in dry season.

Feasibility study of a sea-anchored stratospheric balloon for long-duration flights

Abstract Sea-anchored balloons are stratospheric super-pressure balloons that are anchored to the sea. The sea-anchored balloon is a simple system that has the capability for long-duration flights, fixed-point observations, flexible launch windows, easy telemetry links to ground stations, and quick recoveries. Such balloons are not required to fly through the jet stream while tethered to the ground or sea, because the tether is deployed from a reel on the balloon after reaching a floating altitude. In this study, the feasibility of the sea-anchored balloon is investigated, with particular emphasis on the tether strength, balloon altitude, and system mass, based on the present technological level of the tether’s specific strength. Although the wind distribution with altitude is a dominant factor for feasibility, a sea-anchored balloon with an altitude of about 25 km would be feasible if the velocity of the jet stream is sufficiently low. The sea-anchored balloon can be simply flight-tested, since additional ground facilities and special flight operations are not necessary.