Noise Levels at Different Periods
The table below gives the decibel 10% noise level (in db) for each month in
several period bands. The 10% noise level is defined as the signal
level not exceeded 10% of the time, based on hourly measurements. Each entry in the
table is color coded with reference to the New Low Noise Model (NLNM, Peterson, 1993):
navy, -6 db < value-NLNM < -3 db
blue, -3 db < value-NLNM < 3 db
aqua, 3 db < value-NLNM < 6 db
lime, 6 db < value-NLNM < 9 db
yellow, 9 db < value-NLNM < 12 db
orange, 12 db < value-NLNM < 15 db
red, 15 db < value-NLNM < 20 db
fuchsia, 20 db < value-NLNM < 25 db
silver, value-NLNM < -6 db, value-NLNM > 25 db
Black indicates that there was an insufficient number of hourly measurements to calculate a noise level.
| Month | Chan. | Qual. | # obs. | 518s | 439s | 373s | 316s | 268s | 228s | 193s | 164s | 139s | 118s | 100s | 85s | 72s | 61s | 52s | 44s | 37s | 32s | 27s | 23s | 19s | 16s | 14s | 12s | 10s |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 202405 | LHZ | AR | 322 | -154 | -155 | -157 | -158 | -158 | -158 | -156 | -157 | -156 | -156 | -155 | -155 | -154 | -154 | -153 | -153 | -153 | -152 | -152 | -151 | -151 | -150 | -150 | -149 | -149 |
| 202404 | LHZ | AR | 719 | -147 | -149 | -150 | -151 | -151 | -151 | -151 | -151 | -151 | -150 | -150 | -149 | -149 | -149 | -149 | -148 | -147 | -147 | -147 | -146 | -146 | -145 | -145 | -145 | -144 |
| 202403 | LHZ | AR | 724 | -178 | -181 | -183 | -182 | -183 | -183 | -183 | -183 | -182 | -181 | -181 | -180 | -179 | -178 | -177 | -177 | -176 | -175 | -174 | -172 | -166 | -160 | -157 | -156 | -155 |
| 202402 | LHZ | AR | 341 | -179 | -181 | -182 | -183 | -184 | -184 | -183 | -183 | -182 | -181 | -181 | -180 | -180 | -179 | -178 | -177 | -177 | -176 | -174 | -172 | -165 | -159 | -156 | -157 | -156 |
| 202401 | LHZ | AR | 720 | -178 | -180 | -182 | -183 | -183 | -184 | -183 | -183 | -183 | -182 | -181 | -180 | -180 | -179 | -178 | -177 | -177 | -176 | -174 | -172 | -167 | -161 | -157 | -157 | -155 |
| 202312 | LHZ | AR | 741 | -177 | -180 | -182 | -183 | -183 | -184 | -183 | -183 | -183 | -182 | -181 | -180 | -180 | -179 | -178 | -177 | -176 | -175 | -174 | -173 | -169 | -161 | -160 | -161 | -161 |
| 202311 | LHZ | AR | 685 | -131 | -132 | -133 | -134 | -134 | -134 | -135 | -134 | -134 | -134 | -132 | -132 | -132 | -132 | -132 | -131 | -131 | -130 | -129 | -129 | -128 | -128 | -127 | -127 | -127 |
| 202310 | LHZ | AR | 699 | -138 | -139 | -140 | -141 | -141 | -142 | -142 | -141 | -141 | -139 | -139 | -139 | -139 | -139 | -138 | -137 | -137 | -137 | -136 | -136 | -135 | -135 | -134 | -133 | -134 |
| 202309 | LHZ | AR | 710 | -146 | -147 | -149 | -150 | -150 | -150 | -150 | -149 | -149 | -149 | -149 | -148 | -148 | -147 | -147 | -147 | -146 | -146 | -145 | -145 | -145 | -144 | -144 | -144 | -143 |
| 202308 | LHZ | AR | 679 | -131 | -132 | -134 | -135 | -136 | -136 | -135 | -135 | -135 | -134 | -134 | -133 | -133 | -132 | -131 | -131 | -130 | -130 | -130 | -129 | -129 | -128 | -128 | -127 | -127 |
| 202307 | LHZ | AR | 741 | -163 | -166 | -168 | -169 | -170 | -171 | -171 | -171 | -170 | -170 | -170 | -169 | -168 | -168 | -168 | -167 | -166 | -165 | -164 | -163 | -159 | -154 | -153 | -152 | -151 |
| 202306 | LHZ | AR | 718 | -167 | -170 | -171 | -172 | -173 | -173 | -172 | -172 | -171 | -170 | -170 | -169 | -169 | -168 | -168 | -167 | -166 | -165 | -164 | -163 | -159 | -154 | -152 | -153 | -152 |
| 202305 | LHZ | AR | 742 | -168 | -171 | -172 | -172 | -173 | -173 | -172 | -172 | -171 | -170 | -170 | -169 | -168 | -168 | -167 | -166 | -165 | -164 | -163 | -162 | -156 | -151 | -151 | -151 | -148 |
| 202304 | LHZ | AR | 719 | -168 | -170 | -172 | -173 | -173 | -173 | -172 | -172 | -171 | -170 | -170 | -169 | -168 | -168 | -167 | -166 | -165 | -165 | -163 | -162 | -156 | -150 | -150 | -149 | -146 |
| 202303 | LHZ | AR | 739 | -166 | -168 | -170 | -170 | -171 | -171 | -171 | -170 | -170 | -169 | -169 | -168 | -168 | -167 | -166 | -166 | -165 | -164 | -163 | -160 | -152 | -145 | -143 | -143 | -142 |
| 202302 | LHZ | AR | 519 | -164 | -167 | -168 | -169 | -169 | -170 | -170 | -170 | -169 | -169 | -168 | -167 | -167 | -166 | -166 | -165 | -164 | -164 | -162 | -159 | -153 | -146 | -145 | -146 | -145 |
| 202301 | LHZ | AR | 743 | -118 | -119 | -121 | -122 | -122 | -123 | -122 | -123 | -122 | -122 | -121 | -121 | -120 | -120 | -120 | -120 | -119 | -119 | -119 | -118 | -118 | -118 | -118 | -117 | -117 |
| 202212 | LHZ | AR | 695 | -112 | -114 | -116 | -116 | -117 | -117 | -117 | -117 | -117 | -117 | -116 | -116 | -115 | -116 | -114 | -114 | -114 | -113 | -113 | -113 | -112 | -112 | -112 | -111 | -111 |
| 202211 | LHZ | AR | 713 | -168 | -172 | -176 | -177 | -178 | -179 | -179 | -179 | -179 | -179 | -179 | -178 | -178 | -177 | -177 | -176 | -175 | -174 | -173 | -171 | -166 | -162 | -158 | -158 | -158 |
| 202210 | LHZ | AR | 399 | -175 | -179 | -180 | -182 | -182 | -183 | -182 | -183 | -182 | -181 | -181 | -181 | -180 | -180 | -179 | -178 | -177 | -176 | -175 | -174 | -171 | -165 | -165 | -164 | -161 |
| 202209 | LHZ | AR | 719 | -102 | -104 | -105 | -107 | -108 | -107 | -107 | -107 | -106 | -104 | -103 | -103 | -102 | -102 | -101 | -101 | -99 | -100 | -98 | -97 | -98 | -97 | -97 | -98 | -97 |
| 202208 | LHZ | AR | 742 | -112 | -114 | -115 | -116 | -117 | -117 | -117 | -116 | -116 | -115 | -115 | -114 | -114 | -114 | -113 | -112 | -112 | -111 | -111 | -110 | -110 | -109 | -109 | -108 | -108 |
| 202207 | LHZ | AR | 739 | -112 | -113 | -116 | -116 | -117 | -118 | -119 | -119 | -118 | -118 | -118 | -119 | -118 | -118 | -118 | -118 | -117 | -117 | -116 | -116 | -116 | -115 | -115 | -114 | -114 |
| 202206 | LHZ | AR | 716 | -166 | -168 | -169 | -170 | -171 | -171 | -171 | -170 | -170 | -169 | -169 | -168 | -167 | -166 | -165 | -165 | -164 | -163 | -162 | -160 | -154 | -150 | -150 | -149 | -144 |
| 202205 | LHZ | AR | 739 | -164 | -167 | -169 | -169 | -169 | -170 | -169 | -169 | -169 | -168 | -167 | -166 | -166 | -165 | -164 | -164 | -163 | -162 | -161 | -160 | -156 | -152 | -150 | -150 | -149 |
| 202204 | LHZ | AR | 619 | -167 | -169 | -171 | -171 | -172 | -171 | -171 | -170 | -169 | -169 | -168 | -167 | -166 | -165 | -165 | -164 | -163 | -162 | -161 | -160 | -156 | -150 | -149 | -150 | -146 |
| 202203 | LHZ | AR | 685 | -119 | -121 | -122 | -123 | -123 | -124 | -123 | -124 | -123 | -123 | -123 | -123 | -122 | -122 | -122 | -122 | -121 | -121 | -121 | -121 | -121 | -120 | -120 | -120 | -119 |
| 202202 | LHZ | AR | 672 | -120 | -122 | -123 | -124 | -125 | -125 | -125 | -125 | -125 | -125 | -124 | -124 | -124 | -123 | -123 | -123 | -123 | -123 | -122 | -122 | -122 | -121 | -122 | -121 | -120 |
| 202201 | LHZ | AR | 208 | -124 | -126 | -128 | -129 | -130 | -130 | -130 | -129 | -130 | -130 | -129 | -130 | -129 | -130 | -129 | -130 | -129 | -129 | -129 | -128 | -128 | -129 | -127 | -127 | -126 |
| 202112 | LHZ | AR | 615 | -125 | -128 | -129 | -130 | -131 | -131 | -131 | -131 | -131 | -130 | -131 | -130 | -130 | -130 | -130 | -130 | -129 | -129 | -129 | -129 | -129 | -128 | -128 | -128 | -128 |
| 202111 | LHZ | AR | 680 | -123 | -125 | -127 | -127 | -128 | -128 | -129 | -128 | -128 | -128 | -127 | -127 | -127 | -127 | -126 | -126 | -126 | -126 | -126 | -125 | -125 | -125 | -125 | -125 | -124 |
| 202110 | LHZ | AR | 743 | -120 | -122 | -123 | -124 | -124 | -125 | -124 | -124 | -124 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -122 | -121 | -121 | -121 | -121 | -121 | -120 | -120 |
| 202109 | LHZ | AR | 636 | -119 | -121 | -123 | -123 | -123 | -124 | -124 | -124 | -123 | -122 | -123 | -122 | -122 | -121 | -121 | -121 | -121 | -120 | -120 | -120 | -120 | -120 | -119 | -119 | -119 |
| 202108 | LHZ | AR | 738 | -117 | -119 | -120 | -121 | -121 | -121 | -121 | -120 | -120 | -120 | -119 | -119 | -119 | -118 | -118 | -118 | -118 | -117 | -117 | -117 | -116 | -116 | -116 | -115 | -115 |
| 202107 | LHZ | AR | 737 | -119 | -121 | -122 | -122 | -123 | -123 | -123 | -123 | -123 | -123 | -122 | -122 | -122 | -122 | -121 | -121 | -121 | -121 | -120 | -120 | -120 | -120 | -120 | -120 | -119 |
| 202106 | LHZ | AR | 718 | -117 | -119 | -121 | -122 | -121 | -122 | -121 | -121 | -120 | -120 | -120 | -120 | -119 | -119 | -119 | -119 | -119 | -118 | -118 | -118 | -117 | -117 | -117 | -117 | -116 |
| 202105 | LHZ | AR | 744 | -116 | -117 | -119 | -120 | -120 | -120 | -119 | -119 | -119 | -118 | -118 | -118 | -117 | -117 | -117 | -116 | -116 | -115 | -115 | -115 | -115 | -114 | -114 | -114 | -113 |
| 202104 | LHZ | AR | 719 | -116 | -118 | -118 | -119 | -120 | -120 | -120 | -120 | -119 | -119 | -118 | -118 | -118 | -117 | -117 | -117 | -116 | -116 | -116 | -115 | -115 | -115 | -114 | -114 | -114 |
| 202103 | LHZ | AR | 743 | -114 | -116 | -117 | -118 | -119 | -118 | -118 | -118 | -117 | -117 | -116 | -116 | -116 | -115 | -115 | -114 | -114 | -113 | -113 | -113 | -113 | -112 | -112 | -112 | -111 |
| 202102 | LHZ | AR | 549 | -122 | -124 | -124 | -125 | -125 | -125 | -125 | -125 | -124 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -122 | -121 | -121 | -120 | -120 | -120 | -119 | -119 |
| 202101 | LHZ | AR | 738 | -158 | -162 | -164 | -166 | -166 | -168 | -168 | -167 | -167 | -166 | -166 | -165 | -165 | -165 | -165 | -164 | -163 | -162 | -160 | -155 | -144 | -137 | -137 | -140 | -137 |
| 202012 | LHZ | AR | 743 | -129 | -131 | -132 | -133 | -133 | -133 | -133 | -133 | -132 | -132 | -132 | -131 | -131 | -131 | -130 | -130 | -130 | -130 | -130 | -129 | -128 | -128 | -128 | -127 | -126 |
| 202011 | LHZ | AR | 720 | -166 | -168 | -169 | -170 | -171 | -171 | -171 | -171 | -170 | -169 | -169 | -169 | -168 | -167 | -166 | -166 | -165 | -164 | -163 | -161 | -156 | -150 | -146 | -147 | -146 |
| 202010 | LHZ | AR | 744 | -168 | -170 | -172 | -173 | -174 | -173 | -173 | -173 | -172 | -171 | -170 | -170 | -169 | -168 | -167 | -166 | -166 | -165 | -164 | -162 | -159 | -155 | -154 | -153 | -152 |
| 202009 | LHZ | AR | 718 | -163 | -166 | -168 | -169 | -170 | -171 | -170 | -170 | -170 | -169 | -168 | -168 | -167 | -167 | -165 | -165 | -164 | -163 | -162 | -161 | -157 | -153 | -152 | -151 | -150 |
| 202008 | LHZ | AR | 741 | -119 | -120 | -122 | -122 | -122 | -122 | -123 | -122 | -122 | -121 | -121 | -120 | -120 | -120 | -119 | -119 | -118 | -118 | -118 | -118 | -117 | -117 | -116 | -116 | -116 |
| 202007 | LHZ | AR | 719 | -122 | -123 | -124 | -125 | -125 | -125 | -125 | -125 | -125 | -124 | -123 | -123 | -123 | -122 | -122 | -122 | -121 | -121 | -121 | -120 | -120 | -120 | -120 | -119 | -119 |
| 202006 | LHZ | AR | 707 | -126 | -127 | -129 | -129 | -130 | -130 | -130 | -129 | -129 | -128 | -128 | -128 | -127 | -127 | -127 | -126 | -126 | -125 | -125 | -125 | -124 | -124 | -124 | -124 | -123 |
| 202005 | LHZ | AR | 744 | -125 | -127 | -128 | -128 | -129 | -129 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -126 | -125 | -125 | -125 | -124 | -124 | -124 | -123 | -123 | -123 | -123 | -122 |
| 202004 | LHZ | AR | 718 | -122 | -123 | -124 | -125 | -126 | -126 | -126 | -126 | -125 | -125 | -124 | -124 | -124 | -123 | -123 | -123 | -123 | -122 | -122 | -122 | -122 | -121 | -121 | -121 | -120 |
| 202003 | LHZ | AR | 724 | -123 | -125 | -126 | -126 | -127 | -127 | -126 | -126 | -126 | -126 | -125 | -125 | -125 | -124 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -121 | -122 | -121 |
| 202002 | LHZ | AR | 690 | -125 | -126 | -127 | -128 | -129 | -128 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -126 | -125 | -125 | -125 | -124 | -124 | -124 | -124 | -123 | -123 | -122 | -121 |
| 202001 | LHZ | AR | 741 | -136 | -137 | -139 | -139 | -139 | -140 | -140 | -139 | -139 | -139 | -138 | -138 | -137 | -137 | -137 | -136 | -136 | -136 | -136 | -135 | -135 | -133 | -133 | -133 | -132 |
| 201912 | LHZ | AR | 743 | -130 | -131 | -133 | -133 | -134 | -134 | -134 | -134 | -133 | -133 | -132 | -132 | -132 | -132 | -131 | -131 | -131 | -130 | -130 | -130 | -129 | -128 | -128 | -128 | -126 |
| 201911 | LHZ | AR | 718 | -128 | -129 | -131 | -131 | -131 | -131 | -131 | -131 | -130 | -130 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -128 | -128 | -127 | -126 | -126 | -126 | -125 | -124 |
| 201910 | LHZ | AR | 704 | -162 | -165 | -167 | -169 | -170 | -170 | -170 | -169 | -169 | -168 | -168 | -168 | -167 | -166 | -166 | -165 | -164 | -164 | -163 | -161 | -155 | -149 | -145 | -145 | -143 |
| 201909 | LHZ | AR | 719 | -164 | -166 | -168 | -170 | -170 | -171 | -171 | -170 | -170 | -169 | -169 | -168 | -168 | -167 | -167 | -166 | -165 | -164 | -163 | -162 | -158 | -153 | -151 | -150 | -148 |
| 201908 | LHZ | AR | 738 | -128 | -130 | -131 | -132 | -132 | -132 | -131 | -132 | -131 | -131 | -130 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -126 |
| 201907 | LHZ | AR | 743 | -128 | -130 | -132 | -132 | -133 | -132 | -133 | -132 | -131 | -131 | -131 | -130 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -126 |
| 201906 | LHZ | AR | 706 | -127 | -128 | -129 | -130 | -130 | -130 | -130 | -130 | -129 | -129 | -129 | -129 | -128 | -127 | -127 | -127 | -127 | -126 | -126 | -126 | -125 | -125 | -125 | -124 | -124 |
| 201905 | LHZ | AR | 683 | -167 | -169 | -171 | -171 | -172 | -172 | -171 | -171 | -170 | -169 | -169 | -168 | -168 | -167 | -166 | -166 | -165 | -164 | -163 | -161 | -155 | -151 | -150 | -148 | -144 |
| 201904 | LHZ | AR | 715 | -128 | -130 | -131 | -131 | -132 | -132 | -132 | -132 | -131 | -130 | -130 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -126 | -126 |
| 201903 | LHZ | AR | 744 | -128 | -130 | -131 | -132 | -131 | -132 | -132 | -131 | -131 | -131 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -126 | -126 | -125 |
| 201902 | LHZ | AR | 670 | -166 | -168 | -171 | -171 | -171 | -171 | -171 | -171 | -170 | -169 | -169 | -168 | -168 | -168 | -167 | -167 | -166 | -166 | -164 | -161 | -153 | -145 | -143 | -142 | -143 |
| 201901 | LHZ | AR | 742 | -157 | -161 | -164 | -165 | -166 | -167 | -167 | -167 | -167 | -167 | -167 | -166 | -166 | -166 | -165 | -164 | -164 | -163 | -161 | -157 | -149 | -143 | -141 | -142 | -141 |
| 201812 | LHZ | AR | 743 | -125 | -127 | -128 | -129 | -129 | -129 | -129 | -128 | -128 | -128 | -127 | -127 | -127 | -127 | -126 | -126 | -125 | -125 | -125 | -125 | -124 | -124 | -123 | -123 | -123 |
| 201811 | LHZ | AR | 710 | -122 | -123 | -125 | -126 | -126 | -127 | -126 | -126 | -125 | -125 | -125 | -124 | -124 | -124 | -123 | -123 | -122 | -122 | -121 | -121 | -121 | -121 | -120 | -120 | -119 |
| 201810 | LHZ | AR | 708 | -123 | -125 | -126 | -127 | -127 | -127 | -127 | -126 | -126 | -126 | -126 | -125 | -125 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -122 | -121 | -121 | -121 |
| 201809 | LHZ | AR | 647 | -121 | -123 | -124 | -124 | -125 | -125 | -124 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -121 | -121 | -121 | -120 | -120 | -120 | -120 | -119 | -119 | -119 |
| 201808 | LHZ | AR | 625 | -122 | -123 | -125 | -126 | -126 | -126 | -126 | -126 | -125 | -124 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -122 | -122 | -121 | -121 | -120 | -120 | -120 |
| 201807 | LHZ | AR | 591 | -122 | -123 | -124 | -125 | -126 | -125 | -125 | -125 | -124 | -124 | -124 | -123 | -123 | -123 | -122 | -122 | -122 | -121 | -121 | -121 | -121 | -121 | -120 | -120 | -119 |
| 201806 | LHZ | AR | 717 | -119 | -120 | -121 | -122 | -122 | -123 | -122 | -122 | -122 | -121 | -121 | -121 | -120 | -120 | -119 | -119 | -119 | -118 | -118 | -118 | -117 | -117 | -117 | -117 | -116 |
| 201805 | LHZ | AR | 740 | -119 | -121 | -122 | -122 | -122 | -123 | -123 | -122 | -122 | -122 | -121 | -121 | -120 | -120 | -120 | -120 | -119 | -119 | -118 | -118 | -118 | -117 | -117 | -117 | -117 |
| 201804 | LHZ | AR | 637 | -130 | -131 | -133 | -133 | -134 | -134 | -134 | -134 | -133 | -133 | -132 | -132 | -132 | -131 | -131 | -130 | -131 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -127 |
| 201803 | LHZ | AR | 744 | -127 | -129 | -130 | -131 | -131 | -131 | -131 | -130 | -130 | -130 | -130 | -129 | -129 | -129 | -128 | -128 | -128 | -128 | -127 | -127 | -126 | -126 | -125 | -125 | -125 |
| 201802 | LHZ | AR | 609 | -133 | -135 | -136 | -137 | -138 | -138 | -138 | -138 | -137 | -137 | -136 | -136 | -136 | -136 | -135 | -135 | -135 | -134 | -134 | -133 | -133 | -131 | -131 | -131 | -130 |
| 201801 | LHZ | AR | 728 | -131 | -132 | -133 | -134 | -134 | -134 | -134 | -134 | -133 | -132 | -132 | -132 | -131 | -131 | -131 | -130 | -130 | -129 | -129 | -129 | -129 | -128 | -127 | -127 | -127 |