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 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 202404 | LHZ | AR | 527 | -41 | -41 | -40 | -39 | -38 | -37 | -36 | -35 | -35 | -34 | -35 | -36 | -37 | -38 | -40 | -41 | -43 | -45 | -47 | -49 | -51 | -52 | -53 | -55 | -56 |
| 202403 | LHZ | AR | 716 | -43 | -42 | -41 | -40 | -39 | -37 | -37 | -36 | -35 | -35 | -35 | -36 | -37 | -39 | -40 | -42 | -44 | -46 | -48 | -50 | -52 | -53 | -55 | -56 | -55 |
| 202402 | LHZ | AR | 670 | -44 | -42 | -42 | -41 | -40 | -39 | -38 | -37 | -37 | -37 | -37 | -38 | -40 | -41 | -43 | -45 | -47 | -49 | -51 | -53 | -54 | -55 | -55 | -56 | -56 |
| 202401 | LHZ | AR | 718 | -44 | -43 | -43 | -42 | -41 | -40 | -39 | -39 | -39 | -39 | -39 | -40 | -41 | -43 | -45 | -47 | -49 | -51 | -53 | -55 | -56 | -56 | -55 | -57 | -57 |
| 202312 | LHZ | AR | 731 | -43 | -43 | -42 | -41 | -41 | -40 | -39 | -38 | -38 | -38 | -38 | -39 | -41 | -42 | -44 | -46 | -48 | -50 | -52 | -54 | -55 | -55 | -55 | -55 | -55 |
| 202311 | LHZ | AR | 1 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| 202310 | LHZ | AR | 538 | -40 | -39 | -38 | -37 | -36 | -36 | -35 | -34 | -33 | -33 | -34 | -34 | -36 | -37 | -39 | -41 | -43 | -45 | -48 | -50 | -52 | -53 | -54 | -54 | -55 |
| 202309 | LHZ | AR | 712 | -41 | -40 | -39 | -38 | -38 | -37 | -36 | -36 | -35 | -35 | -35 | -36 | -37 | -39 | -41 | -43 | -44 | -47 | -49 | -51 | -52 | -53 | -55 | -56 | -57 |
| 202308 | LHZ | AR | 358 | -39 | -38 | -37 | -36 | -35 | -35 | -34 | -33 | -33 | -33 | -33 | -34 | -36 | -37 | -39 | -41 | -43 | -45 | -47 | -50 | -51 | -53 | -55 | -57 | -57 |
| 202307 | LHZ | AR | 736 | -38 | -38 | -37 | -36 | -35 | -35 | -34 | -33 | -33 | -33 | -34 | -34 | -35 | -37 | -39 | -41 | -43 | -45 | -47 | -49 | -51 | -53 | -55 | -57 | -59 |
| 202306 | LHZ | AR | 717 | -39 | -39 | -39 | -37 | -36 | -36 | -34 | -34 | -34 | -33 | -34 | -35 | -36 | -37 | -39 | -41 | -43 | -45 | -47 | -49 | -51 | -53 | -55 | -57 | -58 |
| 202305 | LHZ | AR | 668 | -36 | -36 | -35 | -34 | -33 | -32 | -32 | -31 | -31 | -31 | -31 | -32 | -34 | -35 | -37 | -39 | -41 | -43 | -45 | -47 | -49 | -51 | -53 | -55 | -56 |
| 202304 | LHZ | AR | 711 | -38 | -37 | -36 | -35 | -35 | -34 | -33 | -32 | -32 | -32 | -32 | -33 | -34 | -36 | -38 | -40 | -42 | -44 | -46 | -48 | -50 | -52 | -53 | -55 | -57 |
| 202303 | LHZ | AR | 96 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 | 999 |
| 202212 | LHZ | AR | 538 | -36 | -37 | -36 | -34 | -33 | -33 | -32 | -32 | -31 | -31 | -31 | -32 | -33 | -35 | -37 | -38 | -40 | -42 | -45 | -46 | -48 | -49 | -50 | -52 | -53 |
| 202211 | LHZ | AR | 624 | -36 | -36 | -35 | -34 | -33 | -32 | -32 | -31 | -31 | -31 | -31 | -32 | -33 | -35 | -37 | -39 | -41 | -43 | -45 | -47 | -49 | -50 | -51 | -53 | -54 |
| 202210 | LHZ | AR | 143 | -36 | -35 | -35 | -34 | -33 | -32 | -31 | -30 | -29 | -29 | -29 | -30 | -32 | -33 | -35 | -37 | -39 | -41 | -44 | -46 | -47 | -49 | -51 | -52 | -53 |
| 202209 | LHZ | AR | 334 | -37 | -37 | -36 | -35 | -33 | -33 | -32 | -31 | -31 | -31 | -31 | -32 | -33 | -35 | -36 | -38 | -40 | -42 | -44 | -46 | -48 | -50 | -52 | -54 | -55 |
| 202208 | LHZ | AR | 740 | -37 | -36 | -35 | -35 | -34 | -33 | -32 | -32 | -31 | -31 | -31 | -32 | -33 | -35 | -37 | -39 | -40 | -43 | -45 | -47 | -49 | -51 | -53 | -55 | -57 |
| 202207 | LHZ | AR | 601 | -40 | -40 | -39 | -38 | -37 | -36 | -35 | -35 | -35 | -35 | -35 | -36 | -37 | -39 | -41 | -42 | -44 | -46 | -48 | -51 | -52 | -54 | -57 | -58 | -59 |
| 202206 | LHZ | AR | 713 | -141 | -141 | -141 | -143 | -143 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -147 | -148 | -149 | -149 | -150 | -150 | -151 | -151 | -152 | -152 | -152 | -153 | -152 |
| 202204 | LHZ | AR | 401 | -139 | -140 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -147 | -148 | -149 | -149 | -150 | -151 | -151 | -150 | -150 | -150 | -151 |
| 202203 | LHZ | AR | 741 | -140 | -141 | -142 | -142 | -142 | -143 | -143 | -144 | -144 | -145 | -145 | -146 | -147 | -148 | -148 | -149 | -149 | -150 | -150 | -151 | -151 | -150 | -149 | -150 | -149 |
| 202202 | LHZ | AR | 672 | -139 | -140 | -141 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -145 | -146 | -146 | -147 | -147 | -148 | -149 | -149 | -150 | -150 | -149 | -149 | -149 | -149 | -147 |
| 202201 | LHZ | AR | 659 | -139 | -139 | -141 | -141 | -142 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -146 | -147 | -148 | -149 | -149 | -150 | -150 | -151 | -150 | -149 | -148 | -149 | -148 |
| 202112 | LHZ | AR | 697 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -145 | -146 | -146 | -147 | -148 | -148 | -149 | -149 | -150 | -151 | -152 | -152 | -152 | -152 | -151 | -149 | -148 | -149 |
| 202111 | LHZ | AR | 718 | -139 | -140 | -140 | -141 | -141 | -143 | -143 | -144 | -144 | -145 | -146 | -147 | -147 | -148 | -148 | -149 | -150 | -151 | -151 | -152 | -152 | -151 | -150 | -150 | -149 |
| 202110 | LHZ | AR | 743 | -136 | -137 | -137 | -138 | -139 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -146 | -147 | -147 | -148 | -148 | -149 | -149 | -149 | -148 | -148 | -147 |
| 202109 | LHZ | AR | 702 | -135 | -135 | -136 | -137 | -137 | -138 | -138 | -139 | -140 | -141 | -141 | -141 | -142 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -148 | -148 | -148 | -148 | -147 |
| 202108 | LHZ | AR | 677 | -133 | -134 | -135 | -136 | -136 | -137 | -137 | -138 | -139 | -139 | -140 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -148 | -148 | -149 | -149 |
| 202107 | LHZ | AR | 742 | -135 | -135 | -136 | -137 | -137 | -139 | -139 | -139 | -140 | -141 | -141 | -142 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -147 | -148 | -149 | -148 |
| 202106 | LHZ | AR | 716 | -137 | -138 | -139 | -139 | -139 | -140 | -141 | -142 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -148 | -149 | -149 | -150 | -150 | -151 | -151 | -150 |
| 202105 | LHZ | AR | 739 | -135 | -136 | -136 | -137 | -137 | -138 | -138 | -139 | -140 | -141 | -141 | -142 | -142 | -143 | -144 | -145 | -146 | -147 | -147 | -148 | -149 | -149 | -150 | -150 | -148 |
| 202104 | LHZ | AR | 716 | -134 | -136 | -136 | -137 | -137 | -138 | -138 | -139 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -147 | -147 | -147 | -146 |
| 202103 | LHZ | AR | 266 | -136 | -136 | -137 | -139 | -139 | -139 | -139 | -140 | -141 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -145 | -146 | -147 | -147 | -148 | -148 | -148 | -148 | -147 |
| 202101 | LHZ | AR | 122 | -134 | -135 | -134 | -135 | -136 | -136 | -137 | -137 | -138 | -138 | -139 | -140 | -140 | -141 | -141 | -141 | -142 | -143 | -143 | -143 | -143 | -144 | -144 | -142 | -134 |
| 202012 | LHZ | AR | 733 | -135 | -135 | -136 | -136 | -137 | -137 | -138 | -139 | -139 | -140 | -140 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -146 | -145 | -145 | -142 |
| 202011 | LHZ | AR | 717 | -135 | -135 | -136 | -137 | -137 | -137 | -138 | -139 | -139 | -140 | -140 | -142 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -147 | -147 | -147 | -147 |
| 202010 | LHZ | AR | 679 | -135 | -136 | -137 | -137 | -137 | -138 | -138 | -139 | -140 | -140 | -140 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -147 | -147 | -147 | -147 |
| 202009 | LHZ | AR | 716 | -132 | -134 | -134 | -135 | -135 | -135 | -136 | -137 | -137 | -138 | -139 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -146 | -147 | -147 |
| 202008 | LHZ | AR | 725 | -134 | -134 | -135 | -136 | -135 | -136 | -137 | -137 | -138 | -139 | -139 | -140 | -141 | -141 | -142 | -143 | -144 | -144 | -145 | -146 | -147 | -148 | -148 | -149 | -149 |
| 202007 | LHZ | AR | 740 | -132 | -132 | -133 | -133 | -134 | -134 | -135 | -136 | -136 | -137 | -138 | -138 | -139 | -140 | -141 | -142 | -142 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -147 |
| 202006 | LHZ | AR | 711 | -139 | -139 | -140 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -147 | -147 | -148 | -149 | -150 | -150 | -151 | -151 | -152 | -152 | -152 | -153 | -153 | -152 |
| 202005 | LHZ | AR | 741 | -138 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -146 | -147 | -148 | -148 | -149 | -149 | -150 | -151 | -151 | -151 | -151 | -151 | -152 | -150 |
| 202004 | LHZ | AR | 718 | -136 | -137 | -137 | -138 | -138 | -139 | -139 | -140 | -141 | -141 | -142 | -142 | -143 | -144 | -145 | -145 | -146 | -146 | -147 | -148 | -148 | -148 | -148 | -148 | -147 |
| 202003 | LHZ | AR | 743 | -137 | -138 | -139 | -140 | -140 | -141 | -141 | -141 | -142 | -142 | -143 | -143 | -144 | -144 | -145 | -146 | -146 | -146 | -147 | -147 | -148 | -147 | -148 | -148 | -148 |
| 202002 | LHZ | AR | 561 | -136 | -136 | -137 | -138 | -138 | -138 | -139 | -140 | -141 | -141 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -145 | -146 | -147 | -147 | -147 | -146 | -147 | -146 |
| 202001 | LHZ | AR | 253 | -135 | -136 | -136 | -137 | -138 | -139 | -140 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -146 | -146 | -147 | -147 | -146 | -146 | -147 | -145 |
| 201912 | LHZ | AR | 619 | -135 | -137 | -138 | -138 | -139 | -140 | -140 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -148 | -148 | -149 | -148 | -147 | -145 | -145 | -145 |
| 201911 | LHZ | AR | 718 | -138 | -138 | -139 | -140 | -140 | -141 | -141 | -142 | -143 | -143 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -147 | -148 | -148 | -148 | -148 | -148 | -147 | -148 |
| 201910 | LHZ | AR | 741 | -136 | -137 | -137 | -138 | -138 | -140 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -148 | -148 | -148 | -148 | -147 | -147 | -147 |
| 201909 | LHZ | AR | 709 | -136 | -137 | -138 | -138 | -139 | -140 | -140 | -141 | -141 | -142 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -148 | -148 | -149 | -149 | -149 | -149 | -149 | -148 |
| 201908 | LHZ | AR | 736 | -137 | -138 | -138 | -139 | -140 | -141 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -147 | -148 | -148 | -149 | -150 | -151 | -151 | -151 | -152 | -152 | -151 |
| 201907 | LHZ | AR | 706 | -128 | -129 | -130 | -131 | -131 | -131 | -132 | -133 | -134 | -135 | -135 | -136 | -137 | -138 | -138 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 |
| 201906 | LHZ | AR | 712 | -140 | -141 | -142 | -143 | -143 | -143 | -145 | -145 | -146 | -147 | -147 | -148 | -149 | -149 | -150 | -150 | -151 | -151 | -152 | -152 | -153 | -152 | -152 | -153 | -152 |
| 201905 | LHZ | AR | 737 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -145 | -147 | -147 | -147 | -149 | -149 | -150 | -151 | -151 | -152 | -152 | -153 | -153 | -153 | -152 | -153 | -153 | -150 |
| 201904 | LHZ | AR | 715 | -137 | -138 | -139 | -139 | -140 | -140 | -141 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -145 | -146 | -146 | -147 | -147 | -148 | -148 | -148 | -148 | -148 | -147 |
| 201903 | LHZ | AR | 742 | -134 | -134 | -134 | -135 | -135 | -135 | -135 | -136 | -136 | -137 | -137 | -138 | -138 | -139 | -140 | -140 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -146 | -145 |
| 201902 | LHZ | AR | 669 | -137 | -138 | -138 | -138 | -138 | -139 | -140 | -140 | -140 | -140 | -141 | -141 | -141 | -141 | -142 | -142 | -143 | -143 | -143 | -144 | -144 | -144 | -144 | -145 | -144 |
| 201901 | LHZ | AR | 743 | -136 | -137 | -137 | -137 | -138 | -139 | -139 | -139 | -139 | -140 | -140 | -140 | -141 | -141 | -141 | -142 | -142 | -142 | -143 | -143 | -143 | -144 | -144 | -144 | -144 |
| 201812 | LHZ | AR | 725 | -135 | -135 | -135 | -135 | -135 | -135 | -135 | -136 | -136 | -136 | -137 | -137 | -138 | -138 | -139 | -139 | -140 | -140 | -141 | -141 | -142 | -142 | -142 | -143 | -142 |
| 201811 | LHZ | AR | 708 | -135 | -136 | -136 | -136 | -136 | -137 | -137 | -137 | -138 | -138 | -139 | -139 | -140 | -140 | -141 | -141 | -142 | -142 | -143 | -143 | -144 | -144 | -144 | -144 | -144 |
| 201810 | LHZ | AR | 725 | -136 | -136 | -136 | -136 | -137 | -138 | -138 | -139 | -140 | -140 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -147 | -147 | -147 | -146 | -146 |
| 201809 | LHZ | AR | 678 | -135 | -136 | -137 | -137 | -138 | -139 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -148 | -149 | -149 | -148 | -149 | -148 |
| 201808 | LHZ | AR | 661 | -135 | -135 | -136 | -137 | -138 | -139 | -139 | -139 | -140 | -141 | -142 | -143 | -144 | -144 | -145 | -145 | -146 | -147 | -148 | -149 | -149 | -149 | -150 | -151 | -151 |
| 201807 | LHZ | AR | 617 | -139 | -140 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -147 | -147 | -148 | -149 | -150 | -151 | -152 | -153 | -153 | -154 | -154 | -154 | -154 | -155 | -154 |
| 201806 | LHZ | AR | 675 | -141 | -142 | -142 | -143 | -144 | -145 | -145 | -146 | -147 | -148 | -148 | -149 | -150 | -151 | -152 | -152 | -153 | -153 | -154 | -155 | -155 | -154 | -154 | -155 | -153 |
| 201805 | LHZ | AR | 736 | -138 | -139 | -140 | -141 | -141 | -142 | -143 | -144 | -145 | -146 | -147 | -147 | -148 | -149 | -150 | -150 | -151 | -151 | -152 | -152 | -153 | -152 | -153 | -152 | -150 |
| 201804 | LHZ | AR | 710 | -134 | -135 | -135 | -136 | -137 | -138 | -138 | -138 | -139 | -140 | -140 | -141 | -142 | -142 | -143 | -144 | -144 | -145 | -146 | -146 | -147 | -147 | -147 | -148 | -147 |
| 201803 | LHZ | AR | 742 | -132 | -133 | -133 | -134 | -134 | -135 | -136 | -136 | -137 | -138 | -138 | -139 | -140 | -141 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -145 | -145 | -146 | -146 |
| 201802 | LHZ | AR | 602 | -134 | -135 | -135 | -135 | -136 | -137 | -138 | -138 | -139 | -139 | -140 | -141 | -142 | -143 | -143 | -144 | -145 | -145 | -146 | -147 | -147 | -147 | -147 | -147 | -146 |
| 201801 | LHZ | AR | 723 | -138 | -138 | -139 | -140 | -140 | -140 | -141 | -142 | -143 | -143 | -144 | -144 | -145 | -145 | -146 | -147 | -147 | -148 | -148 | -149 | -149 | -148 | -147 | -148 | -146 |