Role Description The Modeling Scientist is responsible for improving model traceability, uncertainty quantification, and predictive trustworthiness in Arva’s ecosystem model predictions. This role is central to advancing Arva’s monitoring, reporting, and verification platform for greenhouse gas emission reductions and removals. Working at the intersection of statistics, machine learning, and process-based ecosystem modeling, this role works closely with ecosystem modelers and data engineers to design robust model traceability and uncertainty frameworks that support transparent, decision-ready outputs for customers, partners, and environmental markets. The Modeling Scientist plays a critical role in translating scientific rigor into real-world impact through credible, auditable modeling systems. Qualifications - 5+ years demonstrated experience in uncertainty quantification, probabilistic modeling, and data model integration - Master’s or PhD degree or equivalent experience in Statistics, Applied Mathematics, Environmental Science, Earth System Science, Biology, or a related quantitative field - Advanced proficiency in Python and scientific computing, with experience building reproducible modeling pipelines - Strong software engineering practices, including writing modular, testable, and well-documented code - Deep commitment to scientific rigor, transparency, and integrity - Experience integrating machine learning with process-based or mechanistic models preferred - Familiarity with ecosystem or Earth system models such as DayCent or CESM preferred - Familiarity with cloud platforms and data systems, including AWS and relational or spatial databases, preferred Requirements - Generate and apply a model traceability framework for ecosystem and biogeochemical models to enable rigorous model testing and improvements. - Design and implement an uncertainty quantification framework, including parameter, structural, aleatory, and epistemic uncertainties. - Apply sensitivity analysis, multivariate testing, and cross-validation to evaluate model robustness and generalizability. - Quantify and communicate model confidence, uncertainty bounds, and performance metrics. - Develop hierarchical and Bayesian approaches for distributed and iterative model optimization. - Apply probabilistic methods to integrate data, models, and uncertainty across scenarios. - Analyze model outputs to diagnose limitations and inform model improvement strategies. - Integrate machine learning techniques with process-based models to improve predictive performance. - Partner with data engineers to implement reproducible, scalable modeling pipelines. - Contribute to the design of model evaluation and optimization workflows. - Communicate uncertainty, confidence intervals, and model performance clearly to stakeholders. - Contribute to scientific reports, model documentation, and peer-reviewed publications. - Support defensible, auditable model outputs for regulatory and credit market review. Benefits - $100k - $160k base salary Company Description Only applicants currently, and in the future, eligible to work in the United States will be considered for this position.

• Manage day-to-day project operations in roles such as principal investigator, project director, or task lead, ensuring deliverables are completed on time, within budget, and to a high standard. • Lead collaborative project teams by developing timelines, coordinating staff assignments. • Identify research problems and design rigorous applied studies, including aligned research questions, methodologies, and analytic plans. • Apply subject-matter expertise to design and implement relevant, responsive, and impactful research and technical assistance projects. • Develop study designs with aligned research questions, methodologies, and analytic plans. • Lead and contribute to proposals for federal, state, foundation, and other clients. • Devise and implement innovative solutions to practical challenges in applied research. • Lead data collection and analysis efforts, including the design of qualitative and/or quantitative data collection tools (e.g., interview protocols, focus group guides, surveys). • Supervise field-based data collection activities, including interviews, observations, focus groups, and document reviews. • Conduct or oversee data analysis using appropriate tools and techniques for various data types. • Communicate study progress and findings clearly and effectively through reports, briefs, visualizations, and other materials. • Represent the organization professionally in client interactions and manage client and stakeholder relationships with awareness of the broader policy and practice landscape. • Communicate effectively, both orally and in writing, with clients, partners, and stakeholders, and foster positive, collaborative working relationships. • Contribute thoughtfully and creatively to project teams.

Provide research and administrative support for global health projects, manage data workflows, assist with regulatory compliance, and contribute to research proposal development and faculty programming within the Division of Global Health Equity.

Title: HPC Computational Scientist Location: USA OH Dayton Full time Hybrid job requisition id RQ217079 Job Description: Type of Requisition: Pipeline Clearance Level Must Currently Possess: None Clearance Level Must Be Able to Obtain: Interim Secret Public Trust/Other Required: None Job Family: Science and Research Job Qualifications: Skills: High Performance Computing (HPC), Python Software Development, Scientific Research, Supercomputing Certifications: None Experience: 3 + years of related experience US Citizenship Required: Yes Job Description: *this is a pipeline requisition for a future need Work with cutting-edge applications that help advance the mission as a HPC Computational Scientist at GDIT. Your work will have you fully immersed in our client’s domain in order to deliver simple solutions for their complex needs. At GDIT, you’ll prioritize the client while we prioritize your career. At GDIT, people are our differentiator. As a HPC Computational Scientist supporting High Performance Computing Modernization Program (HPCMP) User Productivity Enhancement and Training (PET) in Dayton, OH, you will help ensure today is safe and tomorrow is smarter. Our work depends on HPC Computational Scientist joining our team to help solve the complex HPC challenges for DoW scientists and engineers. The HPCMP PET team was created to provide expert computational support for users of the supercomputing computing systems within the DoW. The team serves as a customer-facing presence for the DoW science and technology community, providing SME advice for new initiatives, ongoing projects, and support needs. HOW AN HPC COMPUTATIONAL SCIENTIST WILL MAKE AN IMPACT - Engage with HPC community to build an understanding of HPC needs (both current and future) and stay current with new technology solutions and optimizations - Drive exploration and innovation of new technologies and capabilities relevant to HPC computing and collaborate with other technical teams to evaluate for future implementation. - Innovative mindset: Push to understand needs in-depth and think broadly and creatively about solutions. - Organization: Track and manage tasks across concurrent efforts with different customer groups, and ensure delivery is on schedule and as planned. - Trust: Build and maintain trust of our team and customer base. - Science: Be able to understand (at a high-level) what is driving research and how HPC can best support and enable this. - Attending or leading meetings and discussions with team members and customers to troubleshoot complicated technical problems and brainstorm ways to continuously improve our services. - Working closely with other team members and your Team Lead to enhance and expand fundamental HPC capabilities and complete technical projects. - Occasionally present to senior leadership on HPC best practices, new and interesting cloud technologies, other relevant advances (such as AI &ML), and ways you approached and solved challenging technical issues WHAT YOU’LL NEED TO SUCCEED: - Education: Master of Science (PhD preferred) - Experience: 3+ years of related experience (Minimum of 2 years of relevant HPC experience) - Technical Skills: Experience working on technology projects, which includes meeting the schedule on time and managing customer expectations. Familiarity with commonly used HPC services (i.e. high performance file systems, modules for installing applications, compilers, MPI, OpenMP, profiling tools) - Security Clearance Level: Must be a US citizen and be eligible for a Top Secret clearance - Skills and Abilities: Ability to clearly present ideas to both technical and non-technical users. Experience analyzing solutions components, understanding systems integration challenges, and identifying technology gaps that must be resolved to reach performance targets and functionality requirements. Writing code for use on HPCs. - Preferred Skills: Background in Computer Science or in physics-based computation, such computational structural mechanics (CSM); computational electromagnetics and acoustics (CEA); computational fluid dynamics (CFD) - US Citizenship Required - Location: Dayton, OH (Hybrid). *Please note if you are located elsewhere, relocation assistance may not be offered for this role* GDIT IS YOUR PLACE: ● Full-flex work week to own your priorities at work and at home ● 401K with company match ● Comprehensive health and wellness packages ● Internal mobility team dedicated to helping you own your career ● Professional growth opportunities including paid education and certifications ● Cutting-edge technology you can learn from ● Rest and recharge with paid vacation and holidays The likely salary range for this position is $96,569 - $130,651. This is not, however, a guarantee of compensation or salary. Rather, salary will be set based on experience, geographic location and possibly contractual requirements and could fall outside of this range. Scheduled Weekly Hours: 40 Travel Required: Less than 10% Telecommuting Options: Hybrid Work Location: USA OH Dayton Additional Work Locations: Total Rewards at GDIT: Our benefits package for all US-based employees includes a variety of medical plan options, some with Health Savings Accounts, dental plan options, a vision plan, and a 401(k) plan offering the ability to contribute both pre and post-tax dollars up to the IRS annual limits and receive a company match. To encourage work/life balance, GDIT offers employees full flex work weeks where possible and a variety of paid time off plans, including vacation, sick and personal time, holidays, paid parental, military, bereavement and jury duty leave. To ensure our employees are able to protect their income, other offerings such as short and long-term disability benefits, life, accidental death and dismemberment, personal accident, critical illness and business travel and accident insurance are provided or available. We regularly review our Total Rewards package to ensure our offerings are competitive and reflect what our employees have told us they value most. Our Identity Verification Process: As part of the hiring process, we will ask you to complete an identity verification process that leverages advanced biometrics and artificial intelligence to ensure authenticity and protect against identity fraud. You are expected to be on camera during virtual interviews. We reserve the right to take your picture to verify your identity and prevent fraud. By proceeding, you authorize the collection, processing, and use of your biometric data for identity verification and security purposes. About Our Work: We are GDIT. A global technology and professional services company that delivers consulting, technology and mission services to every major agency across the U.S. government, defense and intelligence community. Our 26,000 experts extract the power of technology to create immediate value and deliver solutions at the edge of innovation. We operate across 50 countries worldwide, offering leading capabilities in digital modernization, AI/ML, Cloud, Cyber and application development. Together with our clients, we strive to create a safer, smarter world by harnessing the power of deep expertise and advanced technology.