Observing system simulation experiments at the National Centers for Environmental Prediction

Abstract

[1] Observing system impact assessments using atmospheric simulation experiments are conducted to provide an objective quantitative evaluation of future observing systems and instruments. Such simulation experiments using a proxy true atmosphere, Nature Run, are known as observing system simulation experiments (OSSEs). Through OSSEs, future observing systems that effectively use data assimilation systems in order to improve weather forecasts can be designed. Various types of simulation experiments have been performed in the past by many scientists, but the OSSE at the National Centers for Environmental Prediction (NCEP) presented in this paper is the most extensive and complete OSSE. The agreement between data impacts from simulated data and the corresponding real data is satisfactory. The NCEP OSSE is also the first OSSE where radiance data from satellites were simulated and assimilated. Since a Doppler wind lidar (DWL) is a very costly instrument, various simulation experiments have been funded and performed. OSSEs that evaluate the data impact of DWL are demonstrated. The results show a potentially powerful impact from DWL. In spite of the many controversies regarding simulation experiments, this paper demonstrates that carefully constructed OSSEs are able to provide useful information that influences the design of future observing systems. Various factors that affect the assessment of the impact are discussed.

Reviews and syntheses: guiding the evolution of the observing system for the carbon cycle through quantitative network design

“…As such techniques have not been applied in a CCDAS context, we only give brief summaries of the approaches that are most popular in the numerical weather prediction (Masutani et al, 2010) and chemical data assimilation (Timmermans et al, 2015) communities. OSSEs are conducted as follows: first, a "true" control vector is selected.…”

The effect of using limited scene-dependent averaging kernels approximations for the implementation of fast observing system simulation experiments targeted on lower tropospheric ozone

“…The NR is used to produce the truth of our simulation world, or the pseudoreality (Masutani et al, 2010b). The NR defines the reality that we wish to characterise with the POs.…”

“…The construction of an observing system involving new instruments can be very costly, especially when dealing with satellites. Then, an objective evaluation of the potential impact of a future satellite observing system is desirable, during the design phase, to select and set-up these costly systems (Masutani et al, 2010b). Historically, OSSEs were first used to evaluate the impact of new observations on numerical weather predictions (Arnold and Clifford, 1986;Lahoz et al, 2005;Tan et al, 2007;Masutani et al, 2010a).…”

Evaluation of the Earth Systems Research Laboratory’s global Observing System Simulation Experiment system

“…More recently, a Joint OSSE collaboration using a 1-month Nature Run from ECMWF yielded a number of OSSE studies for Doppler wind lidar (Marseille et al, 2001;Stoffelen et al, 2006;Masutani et al, 2010). OSSEs have also been conducted using a 3-month NASA generated Nature Run to evaluate the impact of wind lidar data on hurricane prediction (Atlas and Emmitt, 2008).…”

“…As part of a collaborative Joint OSSE between many different institutions, an OSSE framework has been developed and implemented at the National Oceanographic and Atmospheric Administration (NOAA) Earth Systems Research Laboratory (ESRL) in support of the NOAA Unmanned Aircraft Systems (UAS) Programme. This Joint OSSE was initiated to share resources for the creation of an updated OSSE system following the previous global OSSE effort developed in the 1990s (Masutani et al, 2010).…”