New satellite study reveals a widespread transition zone in the sky, challenging climate models

Institute of Atmospheric Physics, Chinese Academy of Sciences

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The blurred line between cloudy and clear skies is captured in this image of forming and evaporating cirriform wisps.

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Credit: Jaume Ruiz de Morales

A new study published in Advances in Atmospheric Sciences has shed light on a previously overlooked but common atmospheric phenomenon: the transition zone (TZ) where clouds and aerosols blend together, making it difficult to tell where one ends and the other begins. These conditions in the sky are more prevalent than previously thought and could be a key to reducing uncertainty in future climate projections.

Clouds and aerosols (tiny suspended particles in the air) are critical players in regulating Earth's temperature, but they remain one of the largest sources of uncertainty in climate models. Traditionally, scientists have classified atmospheric layers as either cloud or aerosol. However, this new research confirms that the real atmosphere is not so binary, often featuring a gradual transition filled with features like wispy cloud fragments or hydrated aerosols that defy simple classification.

The research, led by Jaume Ruiz de Morales from the Universitat de Girona, was honored with the Best Poster Prize at the 2024 International Radiation Symposium (IRS2024) and has been solicited for publication in the symposium's special issue. The work was conducted by an international team from the Universitat de Girona (Spain), the Karlsruhe Institute of Technology (Germany), and the Universitat de Barcelona (Spain).

"Our findings show that the atmosphere is far less black-and-white than climate models assume," said lead author Jaume Ruiz de Morales. "Nearly one in ten measurements reveals this ambiguous transition zone. Ignoring it means we might be missing a critical piece of the puzzle in understanding how the atmosphere manages the Earth's energy budget. Our work calls for questioning how we represent these suspended particles in climate models to achieve more accurate predictions, especially regarding their radiative effects."

To conduct their analysis, the team used a year of high-resolution data from the CALIOP lidar aboard the CALIPSO satellite. They identified these ambiguous TZ layers as those falling within the no-confidence range of a standard cloud-aerosol discrimination algorithm, plus the fuzzy edges of cirrus clouds.

The global assessment revealed that these transition zones are remarkably common, appearing in nearly 10% of all atmospheric profiles measured by the satellite. The study further identified three distinct types of TZ layers:

• Type 1: Layers classified as “cirrus fringes” by the algorithm.
• Type 2: Found at higher altitudes, with properties intermediate between thin ice clouds and aerosols, resembling high wispy clouds.
• Type 3: Found at lower altitudes, with properties between water clouds and aerosols, such as large, hydrated aerosol particles.

Geographically, TZ layers are found worldwide. Type 1 and 2 layers are most frequent in the Intertropical Convergence Zone and mid-latitudes. In contrast, type 3 layers are predominantly found over oceans off the coasts of West Africa and East Asia, regions known for elevated smoke and dusty marine aerosols.

This high frequency of transition zones poses a significant challenge for current climate models, which typically treat clouds and aerosols as separate, distinct entities, that do not fully represent the gradual change detected in observations of the real atmosphere. The research underscores the need to develop more sophisticated representations of atmospheric particles, moving beyond a simple two-category system to improve future climate projections. The team proposed two strategies to improve such parametrizations. To either include an intermediate phase between clouds and aerosols or to treat all suspended particles in the atmosphere as a continuum of states.

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Journal

Advances in Atmospheric Sciences

DOI

10.1007/s00376-025-5052-y 

Article Title

Global Assessment of the Cloud-Aerosol Transition Zone Using CALIPSO

Article Publication Date

17-Nov-2025

 

Lighting and acoustics matter for better work environments in ICUs

Workers in intensive care units were dissatisfied with the lack of natural light and high noise levels

Institute of Science Tokyo

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Healthcare workers were dissatisfied with the high noise levels and lack of natural light in the ICU, and felt that these factors were associated with overall environmental satisfaction and productivity. Architects should consider improving these environmental factors when designing ICUs to enhance productivity.

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Credit: Institute of Science Tokyo

A 3 months study conducted in the intensive care unit (ICU) in Japan, revealed that healthcare workers experience reduced environmental satisfaction and concentration due to lack of natural light and excessive ambient noise. When designing ICUs, architects should focus on increasing natural light and mitigating noise. These factors could help enhance healthcare worker satisfaction, productivity, and quality of patient care.

Most people would agree that worker productivity is affected by the environmental characteristics of a workplace—noise, temperature, lighting, air quality, and more. This is especially true for healthcare workers in intensive care units (ICUs). ICUs are noisy due to life-support machines and healthcare workers moving rapidly to attend to patients, all of which create a stressful and fatiguing environment. Reducing workplace stress could improve healthcare workers’ productivity, reduce the likelihood of mistakes, and thus improve outcomes for patients.

Since April 2024, the Japanese Ministry of Health, Labor, and Welfare has been enforcing work-style reforms for physicians to improve the well-being of healthcare workers. While the reforms focus on capping work hours to prevent exhaustion due to overwork, improving the indoor environmental quality (IEQ) in ICUs is also an important aspect of limiting healthcare workers’ exhaustion. The Japanese Society of Intensive Care Medicine (JSICM) has created a set of guidelines to reduce patient discomfort in ICUs, which could indirectly reduce stress on healthcare workers as well. These guidelines specify a minimum recommended illuminance, an upper limit for ambient noise, and comfortable ranges for temperature and humidity. With regard to air quality in closed indoor spaces, the Ministry of Health, Labor, and Welfare recommends that adequate fresh air be supplied to keep CO2 levels below 1,000 ppm, as a precaution against airborne SARS-CoV-2 transmission. Additionally, the World Health Organization recommends a maximum limit for particulate matter (PM2.5).

A team of researchers from Institute of Science Tokyo (Science Tokyo), Japan, has studied the IEQ of a university hospital’s ICU in Tokyo, Japan, employing objective measurements and subjective assessments using questionnaires. This research project was led by Assistant Professor Wataru Umishio and Associate Professor Takuya Oki of the School of Environment and Society, Science Tokyo, together with Professor Kenji Wakabayashi, Associate Professor Nobuyuki Nosaka, Lecturer Ayako Noguchi, and Lecturer Yoshiki Sento of the Intensive Care Unit, Science Tokyo Hospital. Their findings were made available online on October 15, 2025, and will be published in Volume 92 of the journal Intensive and Critical Care Nursing on February 01, 2026.

“Field measurements were conducted across four IEQ domains—thermal, lighting, acoustic, and air quality—and paired with questionnaire responses from ICU healthcare professionals,” says Umishio, as he described the study, which ran between July and September 2023, adding, “The study explores associations between multi-domain IEQ and overall environmental satisfaction and perceived work productivity.”

Field measurements over 3 months showed that air quality metrics were within the recommended maxima for CO2 and PM2.5. While light illuminance exceeded the JSICM-recommended minimum, there was a significant degree of variation between areas that received adequate natural daylight and those with limited daylight access. Noise levels were entirely outside the JSICM guideline range, and temperatures in single-bed rooms were approximately 3 °C below the recommended values.

These observations aligned with responses to the survey questionnaire, with well over 60% of respondents saying they were at least slightly dissatisfied with the ICU’s overall IEQ. Umishio adds, “Satisfaction levels with thermal, lighting, and acoustic environments were significantly lower. Notably, for the acoustic environment, there were no positive responses, and approximately three-quarters of respondents expressed dissatisfaction.”

Respondents were particularly dissatisfied with the noise from medical equipment and the lack of natural light. Clearly, poor IEQ was impacting the productivity of healthcare workers in the university hospital’s ICU.

These findings provide directions for future ICU designs that improve healthcare worker satisfaction and productivity. As Umishio says, “Prioritizing daylight/circadian-supportive lighting and robust acoustic mitigation—implemented through coordinated efforts between architectural environmental engineering and critical care teams—offers a practical pathway to enhance staff experience and productivity while maintaining patient-centered care.”

 

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About Institute of Science Tokyo (Science Tokyo)
Institute of Science Tokyo (Science Tokyo) was established on October 1, 2024, following the merger between Tokyo Medical and Dental University (TMDU) and Tokyo Institute of Technology (Tokyo Tech), with the mission of “Advancing science and human wellbeing to create value for and with society.”

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Journal

Intensive and Critical Care Nursing

DOI

10.1016/j.iccn.2025.104257 

Method of Research

Observational study

Subject of Research

People

Article Title

Multi-domain indoor environmental quality in intensive care units from a healthcare worker perspective: An observational study in Japan

Article Publication Date

1-Feb-2026

 

Urban infrastructure renewal: Sustainable circulating mixing for urban pile removal

Researchers propose an approach that pumps backfill material from the borehole bottom, showcasing remarkable uniformity throughout the entire depth

Shibaura Institute of Technology

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Researchers propose a sustainable approach for urban pile removal via innovative circulating mixing evaluation.

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Credit: Professor Shinya Inazumi from Shibaura Institute of Technology, Japan Source Link: https://www.sciencedirect.com/science/article/pii/S2666790825002265?via%3Dihub

Many developed nations are facing the simultaneous aging of infrastructure built during periods of rapid economic growth. Japan has reached a critical turning point where numerous buildings and structures constructed in the post-war boom era now require demolition and renewal. The catalyst intensified dramatically after the 2011 Great East Japan Earthquake, which exposed vulnerabilities in structures failing to meet modern disaster prevention standards, leading to sharply increased demolition activity in urban areas.

When structures are demolished, the foundation piles must be removed and classified as industrial waste, yet conventional backfilling methods consistently produce an uneven distribution of material throughout the borehole depth. This technical limitation creates serious risks, including ground settlement, structural tilting of adjacent buildings, and misalignment of newly installed foundations. As a result, the critical backfilling process lacks scientific rigor and quality control mechanisms.

In a recent breakthrough, a team of researchers led by Professor Shinya Inazumi from Shibaura Institute of Technology, Japan, has developed a novel method that can ensure uniform backfilling throughout the entire borehole depth, addressing both immediate safety concerns and long-term infrastructure sustainability. Their innovative findings were made available online on October 15, 2025 and have been published in Volume 29 of the journal Cleaner Engineering and Technology on December 1, 2025.

The proposed circulating mixing method was validated through model tests, field experiments, and advanced numerical simulations using the moving particle semi-implicit (MPS) method within a computer-aided engineering (CAE) framework. These tests demonstrated exceptional uniformity with a coefficient of variation of only 0.036, approximately ten times better than conventional soil improvement methods that typically range from 0.3 to 0.5. In addition, the field tests on 15-meter-deep boreholes confirmed that all samples exceeded the target strength of 1,500 kN/m² with no detection of structurally inadequate weak zones.

“Most significantly, our approach allows engineers to optimize process parameters and improve quality control by employing advanced MPS-CAE computer simulations to predict mixing behavior before construction. Moreover, it addresses Japan's urgent infrastructure renewal needs while promoting sustainability by preventing soil degradation, reducing construction waste, and minimizing the carbon footprint of urban projects,” says Prof. Inazumi.

The findings reveal that this method is especially valuable when constructing high-rise buildings on sites with existing pile foundations, where improperly backfilled boreholes could compromise the stability of new structures worth millions of dollars. Notably, the proposed method prevents ground settlement and structural tilting that could lead to catastrophic failures during seismic events, addressing critical safety concerns in earthquake-prone regions.

“Our study establishes a new standard for geotechnical engineering in urban redevelopment with potential worldwide applications, particularly in cities facing aging infrastructure challenges. In densely populated metropolitan areas like Tokyo, New York, or London, where numerous buildings constructed during post-war economic boom periods now require demolition and reconstruction, this technology ensures safe and efficient site preparation,” says Prof. Inazumi.

The amalgamation of engineering techniques with numerical simulation in the proposed method enables the industry to shift from reactive quality assessment to proactive process optimization, improving the efficiency, safety, durability, and sustainability of urban redevelopment projects, especially in disaster-prone regions.

The paradigm shift in geotechnical engineering practice can help engineering consultancies and construction companies to reassure their clients of construction quality through pre-construction numerical analysis, enhancing transparency and accountability in urban infrastructure projects.

“Our innovative method supports sustainable urban development by minimizing construction waste and reducing the carbon footprint associated with material transportation and disposal. It further offers a pathway to improved geotechnical performance in urban infrastructure development, contributing to disaster resilience, protecting lives and property investments,” concludes Prof. Inazumi.

 

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Reference
DOI: 10.1016/j.clet.2025.101103

 

About Shibaura Institute of Technology (SIT), Japan
Shibaura Institute of Technology (SIT) is a private university with campuses in Tokyo and Saitama. Since the establishment of its predecessor, Tokyo Higher School of Industry and Commerce, in 1927, it has maintained “learning through practice” as its philosophy in the education of engineers. SIT was the only private science and engineering university selected for the Top Global University Project sponsored by the Ministry of Education, Culture, Sports, Science and Technology and had received support from the ministry for 10 years starting from the 2014 academic year. Its motto, “Nurturing engineers who learn from society and contribute to society,” reflects its mission of fostering scientists and engineers who can contribute to the sustainable growth of the world by exposing their over 9,500 students to culturally diverse environments, where they learn to cope, collaborate, and relate with fellow students from around the world.

Website: https://www.shibaura-it.ac.jp/en/

 

About Professor Shinya Inazumi from SIT, Japan
Dr. Shinya Inazumi is a Professor at the College of Engineering, Shibaura Institute of Technology, Japan. He has expertise in civil and environmental engineering, with a strong focus on geotechnical engineering. With over 300 scholarly publications on topics, such as particle-method simulations, sustainable geopolymer materials, and AI-driven urban-resilience mapping, he is recognized as a leading geotechnical researcher. He has been honored with multiple awards, including the MEXT Young Scientists’ Prize (2015), ICE Publishing Environmental Geotechnics Prize (2020), ISSN Outstanding Researcher & Golden Research Awards (2020), and a Best Paper Award at the 14th International Conference on Geotechnique, Construction Materials and Environment (2024).

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Journal

Cleaner Engineering and Technology

DOI

10.1016/j.clet.2025.101103 

Method of Research

Computational simulation/modeling

Subject of Research

Not applicable

Article Title

Sustainable approach to urban pile removal through evaluation of innovative circulating mixing for urban infrastructure renewal

Article Publication Date

1-Dec-2025