ARTMIP Tier 1 Catalogues Purdue Index Ensembles Readme.txt Feb 09, 2021 I. Background This dataset contains 81 indices for the land-falling West-Coast ARs and 81 indices for the inland Midwest ARs studied in Zhang, Tung, and Cleveland (2021, In Search of The Optimal Atmospheric River Index for US Precipitation: A Multifactorial Analysis, JGR in revision, preprint at https://www.essoar.org/doi/10.1002/essoar.10503992.2). The West-Coast region is located between 33--48.5 deg N and 124.375--114.375 deg W; the Midwest region is between 37--47 deg N and 94--84 deg W. The 81 indices in each region were generated by varying four factors: moisture fields (IVT, IWV, or combined IVT+IWV), climatological thresholds (75th, 85th, or 95th percentile), shape criteria (1500, 1800, or 2000 km in length and length:width >= 2), and temporal thresholds (feature persisted for >= 12, 18, or 24 hours with breaks < 24 hours within an event). It is noted that, for the detection of West-Coast land-falling ARs, the length was estimated using only the segment of data over the Pacific; for the ARs penetrating into the Midwest, it was estimated using the entire segment. II. File naming convention 1. Mask file (note that these two masks are identical): MERRA2.ar_mask.Purdue.Xe.nc4 X = m: Midwest region X = w: West-Coast region 2. Index filename: MERRA2.ar_tag.Purdue.XeY.v2.3hourly.Z.nc4 X = m: Midwest region X = w: West-Coast region Y = numbers 1 to 81: Ensemble member identifier (please see below for detail) Z = numbers 1980 to 2017: Year For each member of AR indices in the West-Coast or Midwest region, following criteria applied: Ensemble member 1: ivt-based with 75th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 2: ivt-based with 75th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 3: ivt-based with 75th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 4: ivt-based with 75th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 5: ivt-based with 75th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 6: ivt-based with 75th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 7: ivt-based with 75th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 8: ivt-based with 75th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 9: ivt-based with 75th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 10: iwv-based with 75th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 11: iwv-based with 75th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 12: iwv-based with 75th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 13: iwv-based with 75th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 14: iwv-based with 75th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 15: iwv-based with 75th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 16: iwv-based with 75th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 17: iwv-based with 75th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 18: iwv-based with 75th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 19: ivtiwv-based with 75th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 20: ivtiwv-based with 75th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 21: ivtiwv-based with 75th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 22: ivtiwv-based with 75th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 23: ivtiwv-based with 75th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 24: ivtiwv-based with 75th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 25: ivtiwv-based with 75th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 26: ivtiwv-based with 75th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 27: ivtiwv-based with 75th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 28: ivt-based with 85th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 29: ivt-based with 85th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 30: ivt-based with 85th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 31: ivt-based with 85th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 32: ivt-based with 85th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 33: ivt-based with 85th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 34: ivt-based with 85th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 35: ivt-based with 85th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 36: ivt-based with 85th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 37: iwv-based with 85th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 38: iwv-based with 85th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 39: iwv-based with 85th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 40: iwv-based with 85th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 41: iwv-based with 85th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 42: iwv-based with 85th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 43: iwv-based with 85th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 44: iwv-based with 85th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 45: iwv-based with 85th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 46: ivtiwv-based with 85th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 47: ivtiwv-based with 85th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 48: ivtiwv-based with 85th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 49: ivtiwv-based with 85th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 50: ivtiwv-based with 85th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 51: ivtiwv-based with 85th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 52: ivtiwv-based with 85th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 53: ivtiwv-based with 85th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 54: ivtiwv-based with 85th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 55: ivt-based with 95th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 56: ivt-based with 95th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 57: ivt-based with 95th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 58: ivt-based with 95th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 59: ivt-based with 95th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 60: ivt-based with 95th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 61: ivt-based with 95th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 62: ivt-based with 95th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 63: ivt-based with 95th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 64: iwv-based with 95th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 65: iwv-based with 95th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 66: iwv-based with 95th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 67: iwv-based with 95th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 68: iwv-based with 95th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 69: iwv-based with 95th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 70: iwv-based with 95th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 71: iwv-based with 95th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 72: iwv-based with 95th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria. Ensemble member 73: ivtiwv-based with 95th percentile climate threshold, 1500-km length and 12-hr persistent duration criteria. Ensemble member 74: ivtiwv-based with 95th percentile climate threshold, 1500-km length and 18-hr persistent duration criteria. Ensemble member 75: ivtiwv-based with 95th percentile climate threshold, 1500-km length and 24-hr persistent duration criteria. Ensemble member 76: ivtiwv-based with 95th percentile climate threshold, 1800-km length and 12-hr persistent duration criteria. Ensemble member 77: ivtiwv-based with 95th percentile climate threshold, 1800-km length and 18-hr persistent duration criteria. Ensemble member 78: ivtiwv-based with 95th percentile climate threshold, 1800-km length and 24-hr persistent duration criteria. Ensemble member 79: ivtiwv-based with 95th percentile climate threshold, 2000-km length and 12-hr persistent duration criteria. Ensemble member 80: ivtiwv-based with 95th percentile climate threshold, 2000-km length and 18-hr persistent duration criteria. Ensemble member 81: ivtiwv-based with 95th percentile climate threshold, 2000-km length and 24-hr persistent duration criteria.