Case Studies - K&Z

Chinese University of Hong Kong Studies Outdoor 3D Radiant Fluxes | OTT HydroMet

Blog Team — Wed, 15 Apr 2026 08:34:38 GMT

Measurement of Short and Long Wave Radiation Fluxes

Measurements of the short and long wave radiation fluxes from six directions: up, down, and the four cardinal points - can be combined to give the most accurate outdoor Tmrt with appropriate corrections for the view factor coefficients.

Hong Kong, One of the Highest Density Cities on Earth

By mounting three CNR 4 net radiometers on a tripod, a mobile meteorological station for 3-dimensional radiant fluxes is set up within the outdoor urban environment in Hong Kong, one of the highest density cities on Earth.

Each CNR 4 consists of four sensors, recording both short and long wave radiation from two sides.

Setup for the Three CNR 4 Net Radiometers:

One CNR 4 is mounted horizontally looking at the sky and ground
Another is mounted vertically looking East and West
The third looks North and South

The CNR 4 mobile station will be surrounded by different combinations of tall buildings of different orientations, shapes, surface materials, and so on. The outdoor thermal comfort in the urban setting is being studied in terms of radiant fluxes and hence Tmrt.

An outdoor thermal model of the Hong Kong urban environment will be developed based on the global Tmrt equation in order to seek improvements in urban planning in high density cities.

Article by Mr. Alan Lai of the School of Architecture, The Chinese University of Hong Kong

Energy Balance Studies in India with LAS MkII | OTT HydroMet

Blog Team — Tue, 14 Apr 2026 17:25:17 GMT

Continuous Measurement of Sensible Heat Fluxes

A large aperture scintillometer (LAS), is an open-path optical device for monitoring fluctuations in refractive index of the turbulent atmosphere. The infrared light beam is transmitted to the receiver over path lengths up to 4.5 km (approximately 2.79 miles) that represent a relatively large area.

The Sunniest Province in Canada, Saskatchewan | OTT HydroMet

Blog Team — Tue, 14 Apr 2026 15:26:13 GMT

When is the Sun Shining?

Knowledge of when the sun was shining is used by various industries and sectors - including research, construction, agriculture, tourism, insurance and the legal communities.

An example of insurance and legal interest is automotive accidents, which sometimes occur when the sun is shining squarely into the eyes of the driver, resulting in an inability to see properly. Knowing if the sun was shining at that particular moment can be critical if there is an insurance claim or a legal matter to be settled.

Know When Sunshine is Increasing or Decreasing

Knowing the long-term trend of how the amount of sunshine hours is increasing or decreasing is a key parameter in tracking climate change. It has been projected that the amount of cloud cover will increase and measuring the number of sunshine hours per day, season and year objectively (without the use of models) is critical to monitoring this important climate variable.

The Saskatchewan Research Council (SRC) has operated a principal Climate Reference Station (CRS) in Saskatoon, Saskatchewan since 1963 and bright sunshine has been one of twenty climate variables collected. Kipp & Zonen’s CSD 1 Sunshine Duration Sensor was put into operation in January 2001 and it compared very well to the previous bright sunshine instruments utilized at the CRS.

In 2010 and 2011, SRC expanded its Climate Reference Station network to central Saskatchewan, at the Conservation Learning Centre (CLC) near Prince Albert. A Kipp & Zonen CSD 3 Sunshine Duration Sensor was installed at the new station in the spring of 2011.

SRC Began Recording Sunshine Hours in 1966

The Saskatoon Climate Reference Station began recording bright sunshine hours in 1966, and in the last 48 years has recorded some interesting variability and trends. It is possible for Saskatoon to receive up to 4490.6 hours of bright sunshine in a year, but the average was 2264 hours over the years from 1991 to 2010.

The 1990's had the lowest number of bright sunshine hours for the period of record. The lowest year was 1992, recording 43.8% of the actual to possible hours of bright sunshine.

This drop was due to a downward trend during the summer season of June, July and August (JJA). Since the 1990's, the trend has been towards more annual bright sunshine, increasing further between 2006 and 2012.

Due to the northern latitude, the number of sunshine hours fluctuates markedly depending on the season. The other three seasons, while variable, do not have a strong upwards or downwards trend. The summer downward trend could have been due to various reasons, including three major volcanic eruptions around the globe, plus it is projected that the amount of cloud cover will increase with climate change.

"Bright Sunshine"

‘Bright Sunshine’ is a rather loose and subjective term, largely based upon the Campbell-Stokes glass ball and paper strip instrument, where the length of the ‘burn’ on the paper caused by the focused image of the sun is proportional to the number of ‘bright’ hours.

However, this is highly dependent upon humidity (dampness of the paper), paper type and the observer’s interpretation of ‘burnt’. The instrument requires adjustment every few days to keep the sun’s image on the paper.

The availability of objective electronic instruments without all these drawbacks, and with real-time data available remotely, prompted the World Meteorological Organization (WMO) to propose in 1981 that a direct solar irradiance of 120 W/m2 best represented the threshold of historical ‘Sunny/Not Sunny’ measurements of hours of sunshine in a day. This was finally formalized in 2003 and defined as ‘Sunshine Duration’, with a required daily uncertainty in the number of sunshine hours of ± 10%. The Kipp & Zonen CSD 1 and CSD 3 Sunshine Duration Sensors meet this requirement.

Article by V. Wittrock, Saskatchewan Research Council, Canada

Kipp & Zonen supports the Saskatchewan Research Council with the service and re-calibration of their CSD 1 and CSD 3 Sunshine Duration Sensors.

As a representative explains: “SRC operates two Climate Reference Stations that serve important roles in climate monitoring; in Saskatoon, which celebrated its 50th anniversary in 2013, and at the Conservation Learning Centre near Prince Albert, launched in 2011. Each station has a Kipp & Zonen Sunshine Duration Sensor.

The CRS in Saskatoon is a key site for both the Province of Saskatchewan and the Meteorological Service of Canada climate monitoring network. The CLC station serves as the main meteorological data resource for the many crop development and demonstration programs at the Centre and also as a learning tool in climate monitoring. It is a regular showcase for numerous school tours, research organisations, and the general public.”

Find out more about the Saskatchewan Research Council Climate Reference Stations at: www.src.sk.ca/industries/environment/pages/climate-reference-stations.aspx

Understanding the Future for Glaciers in the Himalayas | OTT HydroMet

Blog Team — Tue, 14 Apr 2026 14:55:30 GMT

One of the most closely studied areas is the Langtang Valley, a catchment of nearly 600 km on the border with China and a quarter of which is covered by glaciers. The highest point is the Langtang Lirung, at 7,234 meters a peak, feared and revered by mountaineers because of the difficulty in reaching the summit.

Most of the rain falls in summer when the monsoon hits the Indian subcontinent and the Langtang region is on its northern frontier, before the Tibetan Plateau. During winter, in the areas above 4,000 meters, many meters of snow accumulate each year and most of it is melting at very fast rates.

Weather Stations Across the Nepalese Himalaya

Studies of precipitation and melt in the valleys of the Nepalese Himalaya are a collaboration of the International Centre for Integrated Mountain Development (ICIMOD), the Nepalese Department of Hydrology and Meteorology, Kathmandu University, and Utrecht University in the Netherlands.

This work has been continued for many years, currently funded by the Norwegian Government, European Research Commission and the Netherlands Organization for Scientific Research. The team is international, comprising of Nepali, Dutch, Belgian, Finnish, Norwegian, German and Austrian co-workers studying the local climate, glaciers, snow cover and how it all relates to water resources.

The project team maintains a number of automatic weather stations (AWS) in the Langtang River catchment on the border with China that help us to judge the quality of larger data sets derived from satellites. The site is visited twice every year to maintain the stations and conduct field experiments. Data is used to make very detailed studies of melt and precipitation in the valley.

The highest automatic weather station is located at 5,200 meters above sea level on the Yala Glacier. Bi-annual glacier mass balance measurements there are among the most detailed in the Himalaya, making it one of the most important sites to help understand the future of glaciers in the region based on field measurements.

The automatic weather station measures air temperature, relative humidity, wind speed and direction, snow depth, as well as all four radiation components with a Kipp & Zonen CNR4 net radiometer.

This data helps in the understanding of the local meteorological drivers of glacier mass change. Yala Glacier overall is losing mass. This is due to intense solar radiation and dry and windy conditions that facilitate snow and ice melting and sublimation (the phase change from solid to gas without going through the liquid state).

Maintenance on Site, Twice a Year

Maintenance of the AWS at this high elevation can be tricky; temperatures in winter fall below -20°C and wind speeds can be very high. Our team visits the station twice a year, before and after the monsoon, to read out data and check equipment functionality.

On clear days, solar radiation at this altitude is fierce. The reflection from the white snow feels like a grill, even when air temperatures are just above the freezing point. When ablation of snow and ice is very strong in the summer, the metal poles of the weather station often need to be re-drilled into the ice by three to four meters. This is to prevent it from melting out and falling over, and potentially damaging sensors like the CNR4 in the process.

Getting data from these stations is not technically difficult, but the local conditions are a challenge. Oxygen levels are 50% lower than in the Netherlands, and that has an effect on one’s concentration. Combine this with freezing temperatures in the morning and the beating sun in the afternoon and you have quite difficult operating conditions.

How the CNR4 Comes Into Play

Future Work - Maintenance and Analysis

After installing new sensors for so many field seasons, the main focus now lies on maintaining these setups and analyzing the data. Future endeavours will hopefully lead to other areas to see whether insights gained here over the years are applicable elsewhere.

Collaborations with local and international partners are key to that, an effort that takes much time in meetings but makes work on these stations even more exciting.

Written by By Jakob F. Steiner, PhD candidate, Faculty of Geosciences , Utrecht University

Find out more about ICIMOD at www.icimod.org and the Utrecht University mountain hydrology projects at www.mountainhydrology.org

Florida Department of Transport Visibility Monitoring System | OTT HydroMet

Blog Team — Tue, 14 Apr 2026 13:22:54 GMT

The Main Challenge - Components Not Standard

The main challenge of this project was that all of the components, except for the SUTRON CDMALinks, were not standard station parts. Therefore, every component had to be extensively researched before choosing it as part of the station.

Each Station is Equipped With:

A visibility sensor
A SUTRON CDMALink Data Logger with Transmitter integrated into the enclosure (18”x14”x12”)
A separate battery enclosure connected via a single cable wiring harness that houses two 55AH batteries to charge the station
Standard fuses
Quick battery disconnects
Indicator lights to show that components are properly connected and powered
Wiring harness that is 21 ft long and is equipped with miniature MS connectors

Stations are Compact and Portable

The stations are compact and portable, so they can be quickly assembled and mounted on a pole as well as safely stored during transportation. Every element of the station was designed for quick installation and storage.

The pelican cases provided protected portability as did the easy, quick disconnects for the batteries, and the large enclosure for batteries to be replaced. The Visibility Monitoring System also included two storage racks for equipment, as well as charging stations for batteries.

Storage racks are powder coated steel that each house:

Three pelican cases
Two battery chargers
Three aluminum enclosures
Twelve batteries
Racks which are about 5 ft high and 6 ft wide

Smart Solar / PV Monitoring with Smart Weather Sensors | OTT HydroMet

Blog Team — Tue, 14 Apr 2026 13:17:24 GMT

Smart Lufft-Sensor on Stavros Niarchos Foundation Cultural Center (SNFCC) in Athens

Blog Team — Tue, 14 Apr 2026 13:16:57 GMT

Building Automation Data using Lufft Smart Weather Sensors

On the photovoltaic roof of the center, the sensor measuring temperature, relative humidity, air pressure, wind velocity and wind direction as well as precipitation, was placed (installed by TEABE EPE).

The station transfers the measurement data to the BMS (Building Management System) via Modbus to monitor and control various sub systems.

Lufft CHM 15k Ceilometer Projects in India

Blog Team — Tue, 14 Apr 2026 13:15:59 GMT

The institute installed two new LiDAR-based Lufft CHM 15k ceilometers for the:

Estimation of the atmospheric aerosol forcing under different sky conditions
Investigation of environmental impacts at regional and global level
Observation of cloud microphysics
Measurement of cloud upper and lower limits
Characterization of cloud density

RWIS Lite – Slim Road Weather Information Systems

Blog Team — Tue, 14 Apr 2026 13:14:52 GMT

Filling the Gaps with Mobile Sensing and RWIS Lite Stations

Ideally, a dense network of road weather monitoring stations reliably provides accurate, hyper-local data. Wherever that is not feasible, be it due to local characteristics or tight budgets, mobile sensing and streamlined Road Weather Information Systems (RWIS) can fill the gaps and ensure availability of essential weather and road surface information.

Reach out for information and pricing for the RWIS Lite solution

Lufft WS100 Precipitation Sensor Helps with Construction Work in Dublin | OTT HydroMet

Kipp & Zonen Blog Team — Tue, 14 Apr 2026 13:14:20 GMT

Delivering Quality and Precision

A new monitoring station was installed to deliver reliable data accurate to the millimeter. The precipitation sensor gives the necessary information whether it’s raining or snowing to avoid false alarms triggered by precipitation. It was provided by the local Lufft partner BARBER InSys.

This large project included the demolition of two vacant commercial units and the construction of premises for 247 beds. This will certainly lead to a social and economic regeneration of the area.