Background
Space Weather
As we embark on the upcoming solar maximum spanning 2023–2026, the space weather community has identified 11 potential breakthroughs in the coming decade. Among these, a pivotal imperative revolves around comprehending the ramifications of solar events on terrestrial life, with a specific focus on their impact on communication, aviation, and human health due to radiation exposure. One fundamental and yet unresolved query pertains to the influence of solar energetic particles (SEPs) stemming from coronal mass ejections (CMEs) and solar flares on terrestrial conditions. This demand for augmented ground-based observations was explicitly underscored by the Senate in the S. Rept. 116-171, 2020, Space Weather Research and Forecasting Act, as well as the 2013 Space Weather Decadal Survey. Presently, North America houses a mere eight neutron monitors (NMs) tasked with tracking high-energy neutron fluctuations. These NMs constitute a critical resource utilized by the NOAA Space Weather Prediction Center (SWPC) in the formulation of solar radiation storm warning levels and radiation exposure estimations for aviation. However, the scant availability of ground-based observations falls short in terms of substantiating space weather model predictions and delving into the underlying model physics and assumptions.
Hydrology and atmospheric science
The hydrologic atmospheric science communities delivered a coordinated strategy document to Congress in 2021 following the NIDIS Reauthorization Act of 2018. The National Integrated Drought Information System (NIDIS) is a multi-agency partnership that coordinates drought monitoring, forecasting, planning, and information at federal, tribal, state, and local levels across the country. From the report, a key gap was the underrepresentation of soil moisture monitoring in forests, grazing lands, and croplands in existing soil moisture networks (i.e., SCAN, CRN, State Mesonets, etc.). The lack of representative soil moisture observations limits the science community from understanding the contribution of these landscapes, resulting in a known bias in land surface models including the operational National Weather Service NOAH model. This bias and underrepresentation impacts model physics, model parameterization, and boundary conditions and thus our understanding of the coupling between the water, energy and carbon cycles. The addition of a soil moisture sensors to existing eddy covariance flux towers sites (Networks from Ameriflux, NEON, LTER, LTAR etc.) will provide invaluable new datasets for the community to help understand the coupled land-surface atmospheric processes and basic science questions impacting climate change.
Ground-based neutron monitoring
Measurements of high-energy neutrons (i.e., lead moderated thermal detectors referred to as neutron monitors, NM) on earth have been vital for understanding the origin of cosmic-rays and how events from the sun impact conditions on earth for seven decades. The operational NM network (Neutron Monitoring Database, NMDB) is a critical piece of global infrastructure. In addition, measurements of low-energy neutrons (i.e., plastic/cadmium moderated thermal detectors referred to as cosmic-ray neutron sensors, CRNS) have been critical for measuring the changes of hydrogen (i.e., water) on earth and in planetary science applications (e.g., Mars rover, planned missions to moon).
The inception of the USA NSF-funded COSMOS project (2009-2012) marked a significant milestone, as it led to the deployment of CRNS instruments worldwide, culminating in the establishment of a loosely connected operational soil moisture network spanning approximately 300 locations across all seven continents. A symbiotic relationship and direct interconnection inherently exist between these two types of monitoring methods and their respective networks. For instance, CRNS measurements rely on NM data to correct for high-energy neutron variation. Conversely, NMs are susceptible to localized alterations in soil moisture and snow conditions, where CRNS can offer valuable insights by mitigating these confounding signals.
In a recent breakthrough, researchers have identified the potential utility of CRNS in detecting space weather events, including GLEs and FDs, particularly at low cutoff rigidities. This demonstrates the expanding horizons of these instruments beyond terrestrial applications into the realm of space weather monitoring.
Given the inherent synergies and direct correlations between low and high-energy neutron monitors, we enthusiastically introduce the Coordinated Cosmic-Ray Observation System (CCROS) Conference. The CCROS Conference aims to unite these distinct research communities, fostering in-depth discussions on cutting-edge scientific inquiries. The culmination of this conference will be the creation of a comprehensive concept paper, encapsulating pivotal scientific queries that can be explored, alongside invaluable insights into the design principles for forthcoming low and high-energy neutron monitoring systems.
