Hyperspectral Microwave Sounding: Spire’s revolutionary approach to weather forecasting

Yet, even after decades of investment, accurate, timely forecasting remains one of the world’s most persistent challenges – especially for industries that rely on high-stakes decision-making.

As climate volatility increases, forecasting complexity does, too. Legacy forecasting models and sparse observational inputs are no longer sufficient for today’s needs. The future of forecasting lies in space-based Earth observation systems, particularly those that deliver high-resolution atmospheric profiling from Low Earth Orbit (LEO).

Among the most impactful technologies enabling this shift are radio occultation (RO) and microwave sounding (MS), and Spire is a global leader in both. We provide governments and commercial partners with near-real-time weather observations from the world’s largest RO constellation, built with scalable, miniaturized payloads that deliver unmatched revisit rates and data fidelity.

Today, we’re expanding that capability with the Hyperspectral Microwave Sounder (HyMS), a next-generation class of sensors designed to provide deeper, higher-resolution atmospheric insights from orbit.

In the sections below, we outline our unique approach to weather forecasting and explain how HyMS-enabled LEMUR satellites will elevate global forecasting accuracy and lead the next evolution in weather intelligence.

Hyperspectral Microwave Sounding for weather forecasting

Before we jump in, let’s answer an important question. What is Hyperspectral Microwave Sounding?

Microwave sounders are crucial for weather forecasting models due to their unique capability to measure within and through the cloud layer. Out of all weather data, they consistently rank the highest impact observations in terms of weather forecast accuracy. Despite their significance, they have been limited in the number of sensing channels they observe. Hyperspectral Microwave Sounding (HyMS) significantly advances this critical remote sensing technique by collecting data across numerous frequency bands in the microwave spectrum. In other words, HyMS technology collects detailed information from the different ‘colors’ of microwave signals, even though these colors can’t be seen with the naked eye.

How is Hyperspectral Microwave Sounding used for weather forecasting?

HyMS sensors capture detailed profiles of the Earth’s atmosphere, measuring important atmospheric variables including temperature, humidity and precipitation. Since the sensors leverage fine spectral resolution across various microwave bands, they can collect data efficiently in all sorts of conditions, including dense cloud cover or heavy rainfall.

The data collected with HyMS enhances the vertical resolution of atmospheric soundings, enables greater accuracy of temperature and water vapour, and provides greater information content on hydrometeors (e.g., rain, snow, ice cloud). A major motive is also to ensure the resilience of this critical observation against the growing threat of radio frequency interference from sources such as 5G and future 6G. Overall, this next-generation hyperspectral approach will substantially improve weather forecasting capabilities.

What’s more is that since the HyMS was developed in a compact form, it can fit neatly on a 16U Nanosatellite platform, showcasing the abilities and advantages of miniaturized space technology for enhanced atmospheric profiling and weather forecasting. Allowing for a miniaturized satellite form factor that can operate in constellation scale in Low Earth Orbit, therefore bringing more reliable and constantly refreshed data from this LEO proximity of collection.

What makes HyMS a step change over traditional microwave sounder technologies?

HyMS technology has been shown through various studies to provide substantial advantages for weather forecasting, including but not limited to the following:

1. As with other microwave sensing technologies, environmental conditions like dense cloud cover or heavy rainfall will not stop data collection efforts from LEO. While visible and infrared sensors are severely limited in their ability to collect data under such conditions, microwave sensors can seamlessly collect data.
2. Spire’s hyperspectral sensor samples at fine (narrow) resolution across a broad continuous bandwidth (>16 GHz instantaneously) versus traditional microwave sensors, which sample only select parts of the atmospheric spectrum. Since each frequency interacts differently with varying levels of the atmosphere, it ultimately allows for more precise measurements of atmospheric parameters at different altitudes (higher vertical resolution). Sampling across the atmospheric spectrum for temperature and water vapour also improves the accuracy of these atmospheric variables.
3. HyMS sensors offer the ability to detect Radio Frequency Interference (RFI) sources from the emerging threat of 5G, future 6G, and telecom service satellites that are moving to higher microwave frequencies adjacent to critical bands. It can do this through its high-resolution sampling and signal processing methods that enable the detection and filtering out of unwanted signals from outside sources.
4. Spire’s progress towards a small satellite constellation of HyMS will improve our ability to observe the same spot on Earth at faster revisit rates, supporting the growing need for real-time weather monitoring and forecasting (Nowcasting).

Spire’s approach to commercializing HyMS-enabled technology

Here at Spire, we’ve developed a unique approach to atmospheric data collection and weather forecasting, pioneered with innovative technologies that bridge the gap between atmospheric observations and weather predictions.

There are three key stages of reaching the commercialization of HyMS-enabled satellites for weather forecasting.

1. Hyperspectral Microwave Sounding (HyMS)

In-Orbit Demonstration of Technology: Stage one involves the development and demonstration of Spire’s proprietary HyMS technology. RAL Space developed this novel sensor, and Spire won the NOAA contract to provide high-resolution atmospheric data by capturing fine measurements across different frequency bands of the microwave spectrum. Spire will undertake building the space mission, manufacturing the satellite for the sensor, devising the launch plan, as well as operations of the satellites once in orbit for the next 4+ years.

2. Operational Hyperspectral Microwave Sounder-Satellite (OHMS-Sat)

Stage two is the integration of Spire’s HyMS technology aboard a commercialized satellite platform. OHMS-Sat represents the transition from our ‘proof-of-concept’ to a practical and scalable solution for real-world weather forecasting applications.

3. AI-driven high-resolution forecasts

Spire will adapt its high-resolution AI weather forecasting models and assimilate the novel hyperspectral microwave data set to deliver advanced forecasting for downstream businesses critically dependent on accurate real-time weather forecasting, such as the renewable energy sector. The weather AI models are driven by the quality of the data they ingest. When combined with its established Radio Occultation data, Spire’s Hyperspectral Microwave Sounder (HyMS) will set new benchmarks for weather forecasting accuracy. These scalable sensors deliver an unprecedented update rate for monitoring rapidly evolving weather events. Paired with advanced AI forecasting algorithms, they not only improve forecast precision but also extend predictive capabilities further into the future.

Each of the above initiatives helps address the traditional limitations of weather forecasting by delivering high-resolution data, enhanced global coverage, and real-time atmospheric insights from satellites in Low Earth Orbit (LEO). Together, they compose a sequence of interconnected weather forecasting solutions, enabling us here at Spire to reinvent how the world approaches forecasting.

Spire’s innovative weather forecasting technologies in action

Spire x NOAA – HyMS-enabled on-orbit demonstration

Spire’s proprietary Hyperspectral Microwave Sounding (HyMS) sensor technology is gaining attention after being awarded a two-year, $4 million NOAA contract to enhance the value and accuracy of NOAA’s Numerical Weather Predictions (NWP). The contract will fund Spire’s in-orbit demonstration of its HyMS-enabled 16U nanosatellites, which will showcase the extent to which HyMS technology can improve nowcasting and forecasting capabilities.

This partnership builds on Spire’s history of successful collaborations with various government agencies, including NOAA’s prior contract with Spire for Radio Occultation (RO) data, and further demonstrates NOAA’s confidence in Spire to deliver actionable, scalable, and real-time insights into the world of weather forecasting.

How will HyMS support NOAA’s primary mission?

Spire’s HyMS-enabled nanosatellites will support NOAA’s mission by filling some of the most critical gaps in atmospheric data.

Traditional weather forecast systems utilize large-scale satellites (carrying multiple sensors and weighing ~ 4 Tonnes), this limits the number of satellites that can be launched and the technology update rate due to the costs and timescales involved with such large missions. Spire’s approach is to use an advanced digital backend enabled microwave sensor and miniaturisation approach. This will provide NOAA, and other NWP centres, complimentary observations to the larger weather satellites (that offer additional essential utility) by ultimately increasing the number of microwave sounders in orbit to improve global coverage. Spire’s unique hyperspectral digital back end approach will introduce new capabilities for enhancing Numerical Weather Prediction models including”.

• Improved vertical resolution of atmospheric temperature and water vapour
• Improvement in the accuracy of atmospheric profiles
• All-Weather Data Collection at High Spectral Resolution
• Radio Frequency interference detection and mitigation

HyMS innovations

This era of HyMS-enabled nanosatellites for weather forecasting is revolutionary for two primary reasons: high performance and miniaturization.

Historically, microwave sounders have been deployed on large multi-sensor platforms (e.g., JPSS or MetOP). Spire has now made significant progress by fitting the advanced capabilities into a small-form satellite bus. The compact design of Spire’s HyMS sensors can fit on a small satellite platform, reaffirming how weight, size, and cost reductions can be applied to atmospheric sensing technology in low-Earth orbit.

Miniaturization unlocks a constellation-ready system that will drive substantially improved life on Earth through better forecasting capabilities. This will be a future-proof observation system that is resilient to emerging radio frequency interference threats and highly complements existing and future government observation infrastructure.

Competitive landscape for HyMS technology

While weather forecasting technologies have been developed and improved decade after decade, Spire’s HyMS technology is making a unique mark on the history of meteorology.

Spire will be the first company to provide hyperspectral microwave weather data across critical temperature and water vapor bands in a satellite. Spire’s ability to combine its HyMS sensor payloads with miniaturized satellite platforms will position it as the frontrunner in cost-effective, scalable, and high-performance solutions moving forward. Beyond those basics, Spire is a global leader in space-based data services, allowing it to provide unmatched expertise to the weather industry and those operating within it.

Spire x STAR-Dundee/Met Office/STFC RAL Space – Operational Hyperspectral Microwave Sounder-Satellite (OHMS-Sat)

Building on the successes of the Hyperspectral Microwave Sounding (HyMS) in-orbit demonstration with NOAA, Spire’s OHMS-Sat project will be a pivotal milestone in the journey toward HyMS-enabled weather forecasting missions.

The ambitious OHMS-Sat initiative is a UK Space Agency-supported program spearheaded by Spire Global in partnership with STAR-Dundee, the UK Met Office, and STF RAL Space. The project will build on HyMS’s prior developments and accelerate its progress towards an operational mission that supplies weather forecasting data to global Numerical Weather Prediction (NWP) centers and creates new and unique weather products.

Collaborations & vision

Led by Spire Global and supported by the UK Space Agency (UKSA), the £4.9 million OHMS-Sat program includes a £3.5 million contribution from UKSA. The contribution comes through the UK’s National Space Innovation Program, which is making a £33 million investment to unlock growth and drive innovation in UK space technologies.

The OHMS-Sat program will asses HyMS in orbit data with the UK Met Office and build and launch the next iteration of HyMS, the Operational Hyperspectral Microwave Sounder – Satellite (OHMS-Sat), in collaboration with;

• STAR-Dundee Ltd, which will develop a state-of-the-art digital back-end ultra-wideband spectrometer, a critical component of the hyperspectral capability.
• The Met Office will carry out a study with the HyMS observations to demonstrate the impact of assimilation in a global NWP system and support airborne demonstrations of hyperspectral microwave sounding to further assess the potential impact of the data.
• STFC RAL Space will provide critical space-qualified mm-wave receiver components and calibration targets for space flight and on-ground testing before launch.

OHMS-Sat next steps

OHMS-Sat is the second stage of bringing Spire’s HyMS technology to its widespread adoption. The coming steps in this transition involve the distribution of funding for key developments, including:

• Testing and validation: STFC RAL Space will develop millimetre wave technology for the HyMS sensor payloads and ensure reliability throughout their operational lifespans in LEO.
• Data assimilation: The Met Office will evaluate the impact of hyperspectral data in existing global weather models to demonstrate the practical application of high-resolution data in an applied context.
• Commercialization: This will support the development of full-scale, commercialized satellite constellations that support Spire’s innovative HyMS payloads, which are designed to enhance global weather forecasting.

Spire x NASA/NOAA – Sounder for Microwave-based Applications (SMBA)

The team was awarded a $4.6 million, 12-month Phase A contract for NOAA’s Near-Earth Orbit Network (NEON) program and participated alongside Ball Aerospace, Northrop Grumman, and Orbital Micro Systems. Each contractor has been awarded a specific amount of money to develop and refine their microwave-sounding designs for LEO. Spire supported this Phase A study on the basis of its unique hyperspectral architecture and microwave expertise.