JRA-25
JRA-25 is a second generation reanalysis product. The model and data assimilation are from the operational system in April 2004. It was the first reanalysis to assimilate wind profiles around tropical cyclones deduced from best-track data, resulting in improved tropical cyclone analysis in a global context. In addition, low-level (stratus) cloud decks along the western subtropical coasts of continents are also better simulated, improving radiation budgets in these regions. A primary goal of JRA-25 is to provide a consistent and high-quality reanalysis dataset for climate research, monitoring, and operational forecasts, especially by improving the coverage and quality of analysis in the Asian region. Note: JRA-25 has been superseded by the JRA-55 reanalysis, a 3rd generation product.
Key Strengths
Long time series of the global precipitation is the best among the other second generation reanalyses
Assimilate wind profiles around tropical cyclones
Low-level cloud along the subtropical western coast of continents is well simulated
Key Limitations
Does not account for satellite biases. Can affect trend; large temperature biases in stratosphere
CO2 held constant for all 25 years
Cold bias in lower stratosphere; Dry bias over Amazon
Research only; No redistribution
Key Figures
Annual temperature range of 2-meter temperature (C) from JRA25. (Climate Data Guide; D. Shea)
Other Information
1.125x1.125/2.5x2.5; 0.4 hPA top
T106, 40 levels
2004