Catalog of landfalling atmospheric rivers along the western coast of North America

We have created a seven-decade-long catalog of atmospheric rivers (ARs) making landfall along the North American west coast based on NCEP Reanalysis (SIO-R1). This catalog provides information on AR magnitude, landfall location, and orientation from 1948 to the near-present.  Understanding the behavior of Atmospheric Rivers and links to large-scale climate variability is critical for water resource management in California and the western US.  The catalog is currently being used in many research applications to improve our understanding and predictability of ARs and associated precipitation along the coast. This dataset is described in Gershunov et al. (2017).  Please cite this reference if you use this dataset, which can be accessed using the link below. 

Download the SIO R1 Catalog


High Resolution record of coastal low cloudiness spanning 20-years

We have developed a high-resolution dataset of coastal low cloudiness (CLC) spanning 20-years using measurements from the NASA GOES satellite.  This high resolution record has, and will continue to play, a critical role in monitoring low clouds at finer spatial resolution (1-4 km) and shorter timescales (half hourly) than was previously available. This dataset is described in  Clemesha et al. (2016).  Please cite this reference if you use this dataset, which can be accessed using the link below.  

Download the GOES derived record of Coastal Low Cloudiness (CLC) including 1 km cloud albedo for San Clemente Island (2020)


Santa Ana Winds Regional Index

We have produced a historical dataset of Santa Ana winds (SAW) spanning seven decades.  This Santa Ana Winds Regional Index (SAWRI) represents regional wind speeds over the SAW domain, which includes the west-facing (south-facing) ranges of the Peninsular (Transverse) mountains as well as the low altitude coastal areas of Southern California.  Two versions of the SAW catalog are available: 1) an hourly SAWRI record (CaRD10-SAWRI) spanning 1948 to 2012 derived from surface winds of the California Reanalysis Downscaling at 10km (CaRD10) dynamical output Guzman-Morales  et al. (2016)  and (2) daily SAWRI record (R1D-SAWRI) expanded to the 1948-2018 period based on the hybrid downscaling of winds from NCEP/NCAR Reanalysis 1  Guzman-Morales  et al. (2019) . Please cite these references if you use these datasets, which can be accessed using the link below.

Download the SAWRI


Coastal Temperature Indices

We also have available for public use our daily Coastal Temperature Indices (CTI) for Tmax and Tmin from 1948 to 2018, which are derived from the 1/16˚ gridded dataset reported in Livneh et al. (2015).  These indices provide daily maximum and minimum temperatures averaged over a Southern California coastal strip – the region with the strongest temperature response during Santa Ana winds.  This dataset was recently used to study hot and cold flavors of Santa Ana winds and associations with California wildfires.  This study, and additional information about the dataset, is reported in  Gershunov  et al. (2021).  The data and variable descriptions can be accessed using the link below.


Historical record of four North Pacific atmospheric circulation regimes important for West Coast weather

We have identified four essential North Pacific atmospheric circulation regimes (called the “NP4 modes”) that modulate coastal vapor transport and precipitation over California on daily to seasonal timescales.  Interactions between these modes drive coastal flow that can result in dry conditions from atmospheric ridging or wet conditions associated with enhanced onshore flow and atmospheric river (AR) landfalls. Joint phase combinations of the NP4 modes have been linked to atmospheric river landfalls, extreme precipitation, and damaging California floods. This dataset is described in Guirguis  et al. (2020). Please cite this reference if you use this dataset, which can be accessed using the link below.

Download the NP4 dataset


Fine Particulate Matter (PM2.5) in Wildfire Smoke

Daily-, ZIP code-specific concentrations of ambient and wildfire-specific PM2.5 were estimated from 1999 through 2012. PM2.5 values are available on 578 ZIP codes in our study region in Southern California. Distinct exposure variables and methods were used to identify ZIP code days exposed to smoke and to isolate wildfire-specific PM2.5 concentrations, all of which are described in detail in our study Aguilera  et al. (2021). The data and variable descriptions can be accessed using the link below.

Download the PM2.5 dataset